diff --git a/README.md b/README.md
index 3d3d6635a2..5edd42845e 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ The following steps describe how to create a JSON:API project.
    public class Person : Identifiable<long>
    {
        [Attr] public string? FirstName { get; set; }
-       [Attr] public string LastName { get; set; } = null!;
+       [Attr] public required string LastName { get; set; }
        [HasMany] public ISet<Person> Children { get; set; } = new HashSet<Person>();
    }
    ```
diff --git a/benchmarks/Deserialization/DeserializationBenchmarkBase.cs b/benchmarks/Deserialization/DeserializationBenchmarkBase.cs
index 018f220994..ce551cf6b8 100644
--- a/benchmarks/Deserialization/DeserializationBenchmarkBase.cs
+++ b/benchmarks/Deserialization/DeserializationBenchmarkBase.cs
@@ -89,7 +89,7 @@ public sealed class IncomingResource : Identifiable<long>
         public float? Attribute05 { get; set; }
 
         [Attr]
-        public string Attribute06 { get; set; } = null!;
+        public required string Attribute06 { get; set; }
 
         [Attr]
         public DateTime? Attribute07 { get; set; }
@@ -104,33 +104,33 @@ public sealed class IncomingResource : Identifiable<long>
         public DayOfWeek Attribute10 { get; set; }
 
         [HasOne]
-        public IncomingResource Single1 { get; set; } = null!;
+        public required IncomingResource Single1 { get; set; }
 
         [HasOne]
-        public IncomingResource Single2 { get; set; } = null!;
+        public required IncomingResource Single2 { get; set; }
 
         [HasOne]
-        public IncomingResource Single3 { get; set; } = null!;
+        public required IncomingResource Single3 { get; set; }
 
         [HasOne]
-        public IncomingResource Single4 { get; set; } = null!;
+        public required IncomingResource Single4 { get; set; }
 
         [HasOne]
-        public IncomingResource Single5 { get; set; } = null!;
+        public required IncomingResource Single5 { get; set; }
 
         [HasMany]
-        public ISet<IncomingResource> Multi1 { get; set; } = null!;
+        public required ISet<IncomingResource> Multi1 { get; set; }
 
         [HasMany]
-        public ISet<IncomingResource> Multi2 { get; set; } = null!;
+        public required ISet<IncomingResource> Multi2 { get; set; }
 
         [HasMany]
-        public ISet<IncomingResource> Multi3 { get; set; } = null!;
+        public required ISet<IncomingResource> Multi3 { get; set; }
 
         [HasMany]
-        public ISet<IncomingResource> Multi4 { get; set; } = null!;
+        public required ISet<IncomingResource> Multi4 { get; set; }
 
         [HasMany]
-        public ISet<IncomingResource> Multi5 { get; set; } = null!;
+        public required ISet<IncomingResource> Multi5 { get; set; }
     }
 }
diff --git a/benchmarks/Serialization/SerializationBenchmarkBase.cs b/benchmarks/Serialization/SerializationBenchmarkBase.cs
index 2ab328c074..3b1f77c15c 100644
--- a/benchmarks/Serialization/SerializationBenchmarkBase.cs
+++ b/benchmarks/Serialization/SerializationBenchmarkBase.cs
@@ -73,7 +73,7 @@ public sealed class OutgoingResource : Identifiable<long>
         public float? Attribute05 { get; set; }
 
         [Attr]
-        public string Attribute06 { get; set; } = null!;
+        public required string Attribute06 { get; set; }
 
         [Attr]
         public DateTime? Attribute07 { get; set; }
diff --git a/docs/home/index.html b/docs/home/index.html
index 7023e2ddc6..388c91d598 100644
--- a/docs/home/index.html
+++ b/docs/home/index.html
@@ -189,7 +189,7 @@ <h4 class="title">Resource</h4>
 {
     [Attr]
     [MaxLength(30)]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowFilter)]
     public string? Summary { get; set; }
@@ -205,7 +205,7 @@ <h4 class="title">Resource</h4>
     public DateTimeOffset LastModifiedAt { get; set; }
 
     [HasOne]
-    public Person Author { get; set; } = null!;
+    public required required Person Author { get; set; }
 
     [HasOne]
     public Person? Reviewer { get; set; }
diff --git a/docs/usage/common-pitfalls.md b/docs/usage/common-pitfalls.md
index 60162cfd37..a4d03fb168 100644
--- a/docs/usage/common-pitfalls.md
+++ b/docs/usage/common-pitfalls.md
@@ -17,7 +17,7 @@ Now let's try to define the resource classes:
 public sealed class WebCustomer : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasOne]
     public LoginAccount? Account { get; set; }
@@ -27,7 +27,7 @@ public sealed class WebCustomer : Identifiable<long>
 public sealed class AdminCustomer : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? CreditRating { get; set; }
@@ -40,7 +40,7 @@ public sealed class AdminCustomer : Identifiable<long>
 public sealed class LoginAccount : Identifiable<long>
 {
     [Attr]
-    public string EmailAddress { get; set; } = null!;
+    public required string EmailAddress { get; set; }
 
     [HasOne]
     public ??? Customer { get; set; }
diff --git a/docs/usage/options.md b/docs/usage/options.md
index 9b900f3973..7af55776c0 100644
--- a/docs/usage/options.md
+++ b/docs/usage/options.md
@@ -141,13 +141,13 @@ public class Person : Identifiable<long>
 {
     [Attr]
     [MinLength(3)]
-    public string FirstName { get; set; } = null!;
+    public required string FirstName { get; set; }
 
     [Attr]
     [Required]
     public int? Age { get; set; }
 
     [HasOne]
-    public LoginAccount Account { get; set; } = null!;
+    public required LoginAccount Account { get; set; }
 }
 ```
diff --git a/docs/usage/resources/attributes.md b/docs/usage/resources/attributes.md
index 42a2aa2600..b683f39154 100644
--- a/docs/usage/resources/attributes.md
+++ b/docs/usage/resources/attributes.md
@@ -11,7 +11,7 @@ public class Person : Identifiable<long>
     public string? FirstName { get; set; }
 
     [Attr]
-    public string LastName { get; set; } = null!;
+    public required string LastName { get; set; }
 }
 ```
 
@@ -54,7 +54,7 @@ Otherwise, the attribute is silently omitted.
 public class User : Identifiable<long>
 {
     [Attr(Capabilities = ~AttrCapabilities.AllowView)]
-    public string Password { get; set; } = null!;
+    public required string Password { get; set; }
 }
 ```
 
diff --git a/docs/usage/resources/inheritance.md b/docs/usage/resources/inheritance.md
index 56c046ef82..7004ddcad6 100644
--- a/docs/usage/resources/inheritance.md
+++ b/docs/usage/resources/inheritance.md
@@ -10,7 +10,7 @@ Resource classes can be part of a type hierarchy. For example:
 public abstract class Human : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasOne]
     public Man? Father { get; set; }
diff --git a/docs/usage/resources/nullability.md b/docs/usage/resources/nullability.md
index 7c600131d0..5fdbe4d0d5 100644
--- a/docs/usage/resources/nullability.md
+++ b/docs/usage/resources/nullability.md
@@ -72,13 +72,13 @@ Example:
 public sealed class Label : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? RgbColor { get; set; }
 
     [HasOne]
-    public Person Creator { get; set; } = null!;
+    public required Person Creator { get; set; }
 
     [HasOne]
     public Label? Parent { get; set; }
diff --git a/docs/usage/resources/relationships.md b/docs/usage/resources/relationships.md
index 30e90c359c..a42cff1bf7 100644
--- a/docs/usage/resources/relationships.md
+++ b/docs/usage/resources/relationships.md
@@ -39,7 +39,7 @@ The next example defines that each car requires an engine, while an engine is op
 public sealed class Car : Identifiable<long>
 {
     [HasOne]
-    public Engine Engine { get; set; } = null!;
+    public required Engine Engine { get; set; }
 }
 
 public sealed class Engine : Identifiable<long>
@@ -264,7 +264,7 @@ There are two ways the exposed relationship name is determined:
 public class TodoItem : Identifiable<long>
 {
     [HasOne(PublicName = "item-owner")]
-    public Person Owner { get; set; } = null!;
+    public required Person Owner { get; set; }
 }
 ```
 
@@ -297,7 +297,7 @@ Otherwise, the relationship (and its related resources, when included) are silen
 public class User : Identifiable<long>
 {
     [HasOne(Capabilities = ~HasOneCapabilities.AllowView)]
-    public LoginAccount Account { get; set; } = null!;
+    public required LoginAccount Account { get; set; }
 }
 ```
 
@@ -339,7 +339,7 @@ Indicates whether POST and PATCH requests can replace the relationship. When sen
 public class User : Identifiable<long>
 {
     [HasOne(Capabilities = ~HasOneCapabilities.AllowSet)]
-    public LoginAccount Account { get; set; } = null!;
+    public required LoginAccount Account { get; set; }
 }
 ```
 
@@ -400,7 +400,7 @@ So for the calculated property to be evaluated correctly, the related entity mus
 public class ShippingAddress : Identifiable<long>
 {
     [Attr]
-    public string Street { get; set; } = null!;
+    public required string Street { get; set; }
 
     [Attr]
     public string? CountryName => Country?.DisplayName;
@@ -412,7 +412,7 @@ public class ShippingAddress : Identifiable<long>
 
 public class Country
 {
-    public string IsoCode { get; set; } = null!;
-    public string DisplayName { get; set; } = null!;
+    public required string IsoCode { get; set; }
+    public required string DisplayName { get; set; }
 }
 ```
diff --git a/src/Examples/DapperExample/Models/LoginAccount.cs b/src/Examples/DapperExample/Models/LoginAccount.cs
index 149fc6c7f8..a40fcaa46e 100644
--- a/src/Examples/DapperExample/Models/LoginAccount.cs
+++ b/src/Examples/DapperExample/Models/LoginAccount.cs
@@ -9,7 +9,7 @@ namespace DapperExample.Models;
 public sealed class LoginAccount : Identifiable<long>
 {
     [Attr]
-    public string UserName { get; set; } = null!;
+    public required string UserName { get; set; }
 
     public DateTimeOffset? LastUsedAt { get; set; }
 
diff --git a/src/Examples/DapperExample/Models/Person.cs b/src/Examples/DapperExample/Models/Person.cs
index 1eb4ecadee..a4f773aab7 100644
--- a/src/Examples/DapperExample/Models/Person.cs
+++ b/src/Examples/DapperExample/Models/Person.cs
@@ -13,7 +13,7 @@ public sealed class Person : Identifiable<long>
     public string? FirstName { get; set; }
 
     [Attr]
-    public string LastName { get; set; } = null!;
+    public required string LastName { get; set; }
 
     // Mistakenly includes AllowFilter, so we can test for the error produced.
     [Attr(Capabilities = AttrCapabilities.AllowView | AttrCapabilities.AllowFilter)]
diff --git a/src/Examples/DapperExample/Models/Tag.cs b/src/Examples/DapperExample/Models/Tag.cs
index cb49ff42fb..bae458c33a 100644
--- a/src/Examples/DapperExample/Models/Tag.cs
+++ b/src/Examples/DapperExample/Models/Tag.cs
@@ -11,7 +11,7 @@ public sealed class Tag : Identifiable<long>
 {
     [Attr]
     [MinLength(1)]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasOne]
     public RgbColor? Color { get; set; }
diff --git a/src/Examples/DapperExample/Models/TodoItem.cs b/src/Examples/DapperExample/Models/TodoItem.cs
index d2f3916268..80b6718eaa 100644
--- a/src/Examples/DapperExample/Models/TodoItem.cs
+++ b/src/Examples/DapperExample/Models/TodoItem.cs
@@ -10,7 +10,7 @@ namespace DapperExample.Models;
 public sealed class TodoItem : Identifiable<long>
 {
     [Attr]
-    public string Description { get; set; } = null!;
+    public required string Description { get; set; }
 
     [Attr]
     [Required]
@@ -26,7 +26,7 @@ public sealed class TodoItem : Identifiable<long>
     public DateTimeOffset? LastModifiedAt { get; set; }
 
     [HasOne]
-    public Person Owner { get; set; } = null!;
+    public required Person Owner { get; set; }
 
     [HasOne]
     public Person? Assignee { get; set; }
diff --git a/src/Examples/DatabasePerTenantExample/Models/Employee.cs b/src/Examples/DatabasePerTenantExample/Models/Employee.cs
index cc79449880..6cc1c4a676 100644
--- a/src/Examples/DatabasePerTenantExample/Models/Employee.cs
+++ b/src/Examples/DatabasePerTenantExample/Models/Employee.cs
@@ -9,11 +9,11 @@ namespace DatabasePerTenantExample.Models;
 public sealed class Employee : Identifiable<Guid>
 {
     [Attr]
-    public string FirstName { get; set; } = null!;
+    public required string FirstName { get; set; }
 
     [Attr]
-    public string LastName { get; set; } = null!;
+    public required string LastName { get; set; }
 
     [Attr]
-    public string CompanyName { get; set; } = null!;
+    public required string CompanyName { get; set; }
 }
diff --git a/src/Examples/GettingStarted/Models/Book.cs b/src/Examples/GettingStarted/Models/Book.cs
index af4f857fdc..211ea73ea8 100644
--- a/src/Examples/GettingStarted/Models/Book.cs
+++ b/src/Examples/GettingStarted/Models/Book.cs
@@ -9,11 +9,11 @@ namespace GettingStarted.Models;
 public sealed class Book : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     public int PublishYear { get; set; }
 
     [HasOne]
-    public Person Author { get; set; } = null!;
+    public required Person Author { get; set; }
 }
diff --git a/src/Examples/GettingStarted/Models/Person.cs b/src/Examples/GettingStarted/Models/Person.cs
index c30b87a889..f3fb215baa 100644
--- a/src/Examples/GettingStarted/Models/Person.cs
+++ b/src/Examples/GettingStarted/Models/Person.cs
@@ -9,7 +9,7 @@ namespace GettingStarted.Models;
 public sealed class Person : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ICollection<Book> Books { get; set; } = new List<Book>();
diff --git a/src/Examples/JsonApiDotNetCoreExample/Models/Person.cs b/src/Examples/JsonApiDotNetCoreExample/Models/Person.cs
index d11fbffff6..daeba78e2d 100644
--- a/src/Examples/JsonApiDotNetCoreExample/Models/Person.cs
+++ b/src/Examples/JsonApiDotNetCoreExample/Models/Person.cs
@@ -13,7 +13,7 @@ public sealed class Person : Identifiable<long>
     public string? FirstName { get; set; }
 
     [Attr]
-    public string LastName { get; set; } = null!;
+    public required string LastName { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowView)]
     [NotMapped]
diff --git a/src/Examples/JsonApiDotNetCoreExample/Models/Tag.cs b/src/Examples/JsonApiDotNetCoreExample/Models/Tag.cs
index 8904ec01a3..bda77ebf7d 100644
--- a/src/Examples/JsonApiDotNetCoreExample/Models/Tag.cs
+++ b/src/Examples/JsonApiDotNetCoreExample/Models/Tag.cs
@@ -11,7 +11,7 @@ public sealed class Tag : Identifiable<long>
 {
     [Attr]
     [MinLength(1)]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<TodoItem> TodoItems { get; set; } = new HashSet<TodoItem>();
diff --git a/src/Examples/JsonApiDotNetCoreExample/Models/TodoItem.cs b/src/Examples/JsonApiDotNetCoreExample/Models/TodoItem.cs
index 68df7cef27..f4238998ff 100644
--- a/src/Examples/JsonApiDotNetCoreExample/Models/TodoItem.cs
+++ b/src/Examples/JsonApiDotNetCoreExample/Models/TodoItem.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreExample.Models;
 public sealed class TodoItem : Identifiable<long>
 {
     [Attr]
-    public string Description { get; set; } = null!;
+    public required string Description { get; set; }
 
     [Attr]
     [Required]
@@ -26,7 +26,7 @@ public sealed class TodoItem : Identifiable<long>
     public DateTimeOffset? LastModifiedAt { get; set; }
 
     [HasOne]
-    public Person Owner { get; set; } = null!;
+    public required Person Owner { get; set; }
 
     [HasOne]
     public Person? Assignee { get; set; }
diff --git a/src/Examples/NoEntityFrameworkExample/Models/Person.cs b/src/Examples/NoEntityFrameworkExample/Models/Person.cs
index 2e7d4a02ab..6e2ea91d68 100644
--- a/src/Examples/NoEntityFrameworkExample/Models/Person.cs
+++ b/src/Examples/NoEntityFrameworkExample/Models/Person.cs
@@ -14,7 +14,7 @@ public sealed class Person : Identifiable<long>
     public string? FirstName { get; set; }
 
     [Attr]
-    public string LastName { get; set; } = null!;
+    public required string LastName { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowView)]
     [NotMapped]
diff --git a/src/Examples/NoEntityFrameworkExample/Models/Tag.cs b/src/Examples/NoEntityFrameworkExample/Models/Tag.cs
index 4a6ae70f49..464459f8ce 100644
--- a/src/Examples/NoEntityFrameworkExample/Models/Tag.cs
+++ b/src/Examples/NoEntityFrameworkExample/Models/Tag.cs
@@ -12,7 +12,7 @@ public sealed class Tag : Identifiable<long>
 {
     [Attr]
     [MinLength(1)]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<TodoItem> TodoItems { get; set; } = new HashSet<TodoItem>();
diff --git a/src/Examples/NoEntityFrameworkExample/Models/TodoItem.cs b/src/Examples/NoEntityFrameworkExample/Models/TodoItem.cs
index 75d948ca7c..eb158cd7bb 100644
--- a/src/Examples/NoEntityFrameworkExample/Models/TodoItem.cs
+++ b/src/Examples/NoEntityFrameworkExample/Models/TodoItem.cs
@@ -11,7 +11,7 @@ namespace NoEntityFrameworkExample.Models;
 public sealed class TodoItem : Identifiable<long>
 {
     [Attr]
-    public string Description { get; set; } = null!;
+    public required string Description { get; set; }
 
     [Attr]
     [Required]
@@ -21,7 +21,7 @@ public sealed class TodoItem : Identifiable<long>
     public long? DurationInHours { get; set; }
 
     [HasOne]
-    public Person Owner { get; set; } = null!;
+    public required Person Owner { get; set; }
 
     [HasOne]
     public Person? Assignee { get; set; }
diff --git a/src/Examples/ReportsExample/Models/Report.cs b/src/Examples/ReportsExample/Models/Report.cs
index e05f8e61a1..688d8a562e 100644
--- a/src/Examples/ReportsExample/Models/Report.cs
+++ b/src/Examples/ReportsExample/Models/Report.cs
@@ -10,8 +10,8 @@ namespace ReportsExample.Models;
 public sealed class Report : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
-    public ReportStatistics Statistics { get; set; } = null!;
+    public required ReportStatistics Statistics { get; set; }
 }
diff --git a/src/Examples/ReportsExample/Models/ReportStatistics.cs b/src/Examples/ReportsExample/Models/ReportStatistics.cs
index 2df01f9b5e..c477596b6f 100644
--- a/src/Examples/ReportsExample/Models/ReportStatistics.cs
+++ b/src/Examples/ReportsExample/Models/ReportStatistics.cs
@@ -5,6 +5,6 @@ namespace ReportsExample.Models;
 [UsedImplicitly(ImplicitUseTargetFlags.Members)]
 public sealed class ReportStatistics
 {
-    public string ProgressIndication { get; set; } = null!;
+    public required string ProgressIndication { get; set; }
     public int HoursSpent { get; set; }
 }
diff --git a/src/JsonApiDotNetCore.Annotations/Resources/Annotations/AttrAttribute.cs b/src/JsonApiDotNetCore.Annotations/Resources/Annotations/AttrAttribute.cs
index 26a660775a..fa18f9d8bd 100644
--- a/src/JsonApiDotNetCore.Annotations/Resources/Annotations/AttrAttribute.cs
+++ b/src/JsonApiDotNetCore.Annotations/Resources/Annotations/AttrAttribute.cs
@@ -21,7 +21,7 @@ public sealed class AttrAttribute : ResourceFieldAttribute
     /// public class Author : Identifiable<long>
     /// {
     ///     [Attr(Capabilities = AttrCapabilities.AllowFilter | AttrCapabilities.AllowSort)]
-    ///     public string Name { get; set; } = null!;
+    ///     public required string Name { get; set; }
     /// }
     /// ]]></code>
     /// </example>
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/BroadcastComment.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/BroadcastComment.cs
index e76da97f29..0ea8e5b8ba 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/BroadcastComment.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/BroadcastComment.cs
@@ -9,11 +9,11 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Archiving;
 public sealed class BroadcastComment : Identifiable<long>
 {
     [Attr]
-    public string Text { get; set; } = null!;
+    public required string Text { get; set; }
 
     [Attr]
     public DateTimeOffset CreatedAt { get; set; }
 
     [HasOne]
-    public TelevisionBroadcast AppliesTo { get; set; } = null!;
+    public required TelevisionBroadcast AppliesTo { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionBroadcast.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionBroadcast.cs
index 8476036013..14a1776360 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionBroadcast.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionBroadcast.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Archiving;
 public sealed class TelevisionBroadcast : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     public DateTimeOffset AiredAt { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionNetwork.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionNetwork.cs
index cbbe3219cc..4dbc8338e0 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionNetwork.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionNetwork.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Archiving;
 public sealed class TelevisionNetwork : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<TelevisionStation> Stations { get; set; } = new HashSet<TelevisionStation>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionStation.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionStation.cs
index 1bfab54405..9f8d47e076 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionStation.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionStation.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Archiving;
 public sealed class TelevisionStation : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<TelevisionBroadcast> Broadcasts { get; set; } = new HashSet<TelevisionBroadcast>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Lyric.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Lyric.cs
index af1ac9e18b..b0c5df488c 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Lyric.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Lyric.cs
@@ -12,7 +12,7 @@ public sealed class Lyric : Identifiable<long>
     public string? Format { get; set; }
 
     [Attr]
-    public string Text { get; set; } = null!;
+    public required string Text { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.None)]
     public DateTimeOffset CreatedAt { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/MusicTrack.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/MusicTrack.cs
index 0abf7385ee..8869171be9 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/MusicTrack.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/MusicTrack.cs
@@ -13,7 +13,7 @@ public sealed class MusicTrack : Identifiable<Guid>
     public override Guid Id { get; set; }
 
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     [Range(1, 24 * 60)]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Playlist.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Playlist.cs
index 0d6409e761..653b3aede8 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Playlist.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Playlist.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.AtomicOperations;
 public sealed class Playlist : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     [NotMapped]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/RecordCompany.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/RecordCompany.cs
index 5e0509a57f..005cad3611 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/RecordCompany.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/RecordCompany.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.AtomicOperations;
 public sealed class RecordCompany : Identifiable<short>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? CountryOfResidence { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Actor.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Actor.cs
index 262fab70f1..ae431f9c30 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Actor.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Actor.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Authorization.Scopes;
 public sealed class Actor : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public DateTime BornAt { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Genre.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Genre.cs
index f5bcba8fe2..d48443caae 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Genre.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Genre.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Authorization.Scopes;
 public sealed class Genre : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<Movie> Movies { get; set; } = new HashSet<Movie>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Movie.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Movie.cs
index 4e52ff2728..eace8d3741 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Movie.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Authorization/Scopes/Movie.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Authorization.Scopes;
 public sealed class Movie : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     public int ReleaseYear { get; set; }
@@ -18,7 +18,7 @@ public sealed class Movie : Identifiable<long>
     public int DurationInSeconds { get; set; }
 
     [HasOne]
-    public Genre Genre { get; set; } = null!;
+    public required Genre Genre { get; set; }
 
     [HasMany]
     public ISet<Actor> Cast { get; set; } = new HashSet<Actor>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Blobs/ImageContainer.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Blobs/ImageContainer.cs
index 3462cdb2df..6b746389a5 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Blobs/ImageContainer.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Blobs/ImageContainer.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Blobs;
 public sealed class ImageContainer : Identifiable<long>
 {
     [Attr]
-    public string FileName { get; set; } = null!;
+    public required string FileName { get; set; }
 
     [Attr]
     public byte[] Data { get; set; } = [];
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Dealership.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Dealership.cs
index c8574b320e..15275a10fc 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Dealership.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Dealership.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.CompositeKeys;
 public sealed class Dealership : Identifiable<long>
 {
     [Attr]
-    public string Address { get; set; } = null!;
+    public required string Address { get; set; }
 
     [HasMany]
     public ISet<Car> Inventory { get; set; } = new HashSet<Car>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Engine.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Engine.cs
index 428b65fbb7..11f33a5230 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Engine.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/Engine.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.CompositeKeys;
 public sealed class Engine : Identifiable<long>
 {
     [Attr]
-    public string SerialCode { get; set; } = null!;
+    public required string SerialCode { get; set; }
 
     [HasOne]
     public Car? Car { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/Policy.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/Policy.cs
index 745b137069..a49a2217fd 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/Policy.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/Policy.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ContentNegotiation;
 public sealed class Policy : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Civilian.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Civilian.cs
index bd8d401fcb..5c11d5b464 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Civilian.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Civilian.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.CustomRoutes;
 public sealed class Civilian : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     [Range(1900, 2050)]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Town.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Town.cs
index 5ef7dee922..c7d97e81ff 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Town.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/CustomRoutes/Town.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.CustomRoutes;
 public sealed class Town : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public double Latitude { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Building.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Building.cs
index 84cce7149c..3c45d68341 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Building.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Building.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.EagerLoading;
 public sealed class Building : Identifiable<long>
 {
     [Attr]
-    public string Number { get; set; } = null!;
+    public required string Number { get; set; }
 
     [Attr]
     [NotMapped]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/City.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/City.cs
index 03ab50c832..bc302574a6 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/City.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/City.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.EagerLoading;
 public sealed class City : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public IList<Street> Streets { get; set; } = new List<Street>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Door.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Door.cs
index 1e60b1bd71..5f564732a7 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Door.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Door.cs
@@ -8,5 +8,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.EagerLoading;
 public sealed class Door
 {
     public int Id { get; set; }
-    public string Color { get; set; } = null!;
+    public required string Color { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/State.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/State.cs
index 190c745988..1ce3840f5a 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/State.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/State.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.EagerLoading;
 public sealed class State : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public IList<City> Cities { get; set; } = new List<City>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Street.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Street.cs
index 05673ec5d9..55b41020cf 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Street.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/EagerLoading/Street.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.EagerLoading;
 public sealed class Street : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowView)]
     [NotMapped]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ExceptionHandling/ConsumerArticle.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ExceptionHandling/ConsumerArticle.cs
index 64ba92a917..9695cabbf4 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ExceptionHandling/ConsumerArticle.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ExceptionHandling/ConsumerArticle.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ExceptionHandling;
 public sealed class ConsumerArticle : Identifiable<long>
 {
     [Attr]
-    public string Code { get; set; } = null!;
+    public required string Code { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/ArtGallery.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/ArtGallery.cs
index 7331130cf2..bdee0f3d01 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/ArtGallery.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/ArtGallery.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.HostingInIIS;
 public sealed class ArtGallery : Identifiable<long>
 {
     [Attr]
-    public string Theme { get; set; } = null!;
+    public required string Theme { get; set; }
 
     [HasMany]
     public ISet<Painting> Paintings { get; set; } = new HashSet<Painting>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/Painting.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/Painting.cs
index 0053dc9c2b..c5cf50b2d6 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/Painting.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/HostingInIIS/Painting.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.HostingInIIS;
 public sealed class Painting : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [HasOne]
     public ArtGallery? ExposedAt { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/BankAccount.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/BankAccount.cs
index 663b2a3bd6..b22a964547 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/BankAccount.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/BankAccount.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.IdObfuscation;
 public sealed class BankAccount : ObfuscatedIdentifiable
 {
     [Attr]
-    public string Iban { get; set; } = null!;
+    public required string Iban { get; set; }
 
     [HasMany]
     public IList<DebitCard> Cards { get; set; } = new List<DebitCard>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/DebitCard.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/DebitCard.cs
index 99f0154147..249d5f58e4 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/DebitCard.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/IdObfuscation/DebitCard.cs
@@ -9,11 +9,11 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.IdObfuscation;
 public sealed class DebitCard : ObfuscatedIdentifiable
 {
     [Attr]
-    public string OwnerName { get; set; } = null!;
+    public required string OwnerName { get; set; }
 
     [Attr]
     public short PinCode { get; set; }
 
     [HasOne]
-    public BankAccount Account { get; set; } = null!;
+    public required BankAccount Account { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemDirectory.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemDirectory.cs
index 4265dc688e..4b15539403 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemDirectory.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemDirectory.cs
@@ -14,7 +14,7 @@ public sealed class SystemDirectory : Identifiable<int>
 
     [Attr(PublicName = "directoryName")]
     [RegularExpression(@"^[\w\s]+$")]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     [Required]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemFile.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemFile.cs
index d2845cca84..1dd249f80a 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemFile.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemFile.cs
@@ -11,7 +11,7 @@ public sealed class SystemFile : Identifiable<long>
 {
     [Attr]
     [MinLength(1)]
-    public string FileName { get; set; } = null!;
+    public required string FileName { get; set; }
 
     [Attr]
     [Required]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemVolume.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemVolume.cs
index b283b551b1..6622088531 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemVolume.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/InputValidation/ModelState/SystemVolume.cs
@@ -12,5 +12,5 @@ public sealed class SystemVolume : Identifiable<long>
     public string? Name { get; set; }
 
     [HasOne]
-    public SystemDirectory RootDirectory { get; set; } = null!;
+    public required SystemDirectory RootDirectory { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoAlbum.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoAlbum.cs
index 32bdf79a40..8669f37843 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoAlbum.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoAlbum.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Links;
 public sealed class PhotoAlbum : Identifiable<Guid>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<Photo> Photos { get; set; } = new HashSet<Photo>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoLocation.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoLocation.cs
index 092851fbdd..9ac9f51ac4 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoLocation.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Links/PhotoLocation.cs
@@ -19,7 +19,7 @@ public sealed class PhotoLocation : Identifiable<long>
     public double Longitude { get; set; }
 
     [HasOne]
-    public Photo Photo { get; set; } = null!;
+    public required Photo Photo { get; set; }
 
     [HasOne(Links = LinkTypes.None)]
     public PhotoAlbum? Album { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Logging/AuditEntry.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Logging/AuditEntry.cs
index 827a8cf472..1a7835817f 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Logging/AuditEntry.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Logging/AuditEntry.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Logging;
 public sealed class AuditEntry : Identifiable<long>
 {
     [Attr]
-    public string UserName { get; set; } = null!;
+    public required string UserName { get; set; }
 
     [Attr]
     public DateTimeOffset CreatedAt { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/ProductFamily.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/ProductFamily.cs
index bb72fd5392..e750563843 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/ProductFamily.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/ProductFamily.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Meta;
 public sealed class ProductFamily : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public IList<SupportTicket> Tickets { get; set; } = new List<SupportTicket>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/SupportTicket.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/SupportTicket.cs
index b04c0ec2ab..2e5a94fa31 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/SupportTicket.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Meta/SupportTicket.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Meta;
 public sealed class SupportTicket : Identifiable<long>
 {
     [Attr]
-    public string Description { get; set; } = null!;
+    public required string Description { get; set; }
 
     [HasOne]
     public ProductFamily? ProductFamily { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainGroup.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainGroup.cs
index dd87456892..cc4e33e4cd 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainGroup.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainGroup.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Microservices;
 public sealed class DomainGroup : Identifiable<Guid>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<DomainUser> Users { get; set; } = new HashSet<DomainUser>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainUser.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainUser.cs
index 0efb562355..d47d518e25 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainUser.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Microservices/DomainUser.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Microservices;
 public sealed class DomainUser : Identifiable<Guid>
 {
     [Attr]
-    public string LoginName { get; set; } = null!;
+    public required string LoginName { get; set; }
 
     [Attr]
     public string? DisplayName { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebProduct.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebProduct.cs
index a2c41c5ede..dbcac94b7a 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebProduct.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebProduct.cs
@@ -9,11 +9,11 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.MultiTenancy;
 public sealed class WebProduct : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public decimal Price { get; set; }
 
     [HasOne]
-    public WebShop Shop { get; set; } = null!;
+    public required WebShop Shop { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebShop.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebShop.cs
index f191344fcc..2da0d679f6 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebShop.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/MultiTenancy/WebShop.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.MultiTenancy;
 public sealed class WebShop : Identifiable<long>, IHasTenant
 {
     [Attr]
-    public string Url { get; set; } = null!;
+    public required string Url { get; set; }
 
     public Guid TenantId { get; set; }
 
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Appointment.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Appointment.cs
index ba3ea783df..d9529099ea 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Appointment.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Appointment.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class Appointment : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     public string? Description { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Blog.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Blog.cs
index b58c446ced..3e23b11a38 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Blog.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Blog.cs
@@ -9,10 +9,10 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class Blog : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
-    public string PlatformName { get; set; } = null!;
+    public required string PlatformName { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.All & ~(AttrCapabilities.AllowCreate | AttrCapabilities.AllowChange))]
     public bool ShowAdvertisements => PlatformName.EndsWith("(using free account)", StringComparison.Ordinal);
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/BlogPost.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/BlogPost.cs
index f0382f90a4..c72ee7256a 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/BlogPost.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/BlogPost.cs
@@ -9,10 +9,10 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class BlogPost : Identifiable<long>
 {
     [Attr]
-    public string Caption { get; set; } = null!;
+    public required string Caption { get; set; }
 
     [Attr]
-    public string Url { get; set; } = null!;
+    public required string Url { get; set; }
 
     [HasOne]
     public WebAccount? Author { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Comment.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Comment.cs
index 2e78f4e999..c7442d8bc3 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Comment.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Comment.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class Comment : Identifiable<long>
 {
     [Attr]
-    public string Text { get; set; } = null!;
+    public required string Text { get; set; }
 
     [Attr]
     public DateTime CreatedAt { get; set; }
@@ -21,5 +21,5 @@ public sealed class Comment : Identifiable<long>
     public WebAccount? Author { get; set; }
 
     [HasOne]
-    public BlogPost Parent { get; set; } = null!;
+    public required BlogPost Parent { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Human.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Human.cs
index 1e2c01d73b..709e74e0c9 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Human.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Human.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public abstract class Human : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasOne]
     public Man? Father { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Label.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Label.cs
index 9b22c051cf..6e69efd324 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Label.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Label.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class Label : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public LabelColor Color { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/WebAccount.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/WebAccount.cs
index c32431ec84..02fa63124c 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/WebAccount.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/WebAccount.cs
@@ -9,19 +9,19 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class WebAccount : Identifiable<long>
 {
     [Attr]
-    public string UserName { get; set; } = null!;
+    public required string UserName { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.All & ~AttrCapabilities.AllowView)]
-    public string Password { get; set; } = null!;
+    public required string Password { get; set; }
 
     [Attr]
-    public string DisplayName { get; set; } = null!;
+    public required string DisplayName { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.All & ~(AttrCapabilities.AllowFilter | AttrCapabilities.AllowSort))]
     public DateTime? DateOfBirth { get; set; }
 
     [Attr]
-    public string EmailAddress { get; set; } = null!;
+    public required string EmailAddress { get; set; }
 
     [HasOne(Capabilities = HasOneCapabilities.All & ~HasOneCapabilities.AllowView)]
     public Human? Person { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Woman.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Woman.cs
index 8e1044b2de..29348c83c1 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Woman.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/QueryStrings/Woman.cs
@@ -8,7 +8,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.QueryStrings;
 public sealed class Woman : Human
 {
     [Attr]
-    public string MaidenName { get; set; } = null!;
+    public required string MaidenName { get; set; }
 
     [Attr]
     public int Age { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/RgbColor.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/RgbColor.cs
index 28762384c9..9fd97e08df 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/RgbColor.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/RgbColor.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ReadWrite;
 public sealed class RgbColor : Identifiable<string?>
 {
     [Attr]
-    public string DisplayName { get; set; } = null!;
+    public required string DisplayName { get; set; }
 
     [HasOne]
     public WorkItemGroup? Group { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemGroup.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemGroup.cs
index b5b94258f2..d65f8b8fa9 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemGroup.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemGroup.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ReadWrite;
 public sealed class WorkItemGroup : Identifiable<Guid>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public bool IsPublic { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemToWorkItem.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemToWorkItem.cs
index 23a62b0e4a..ffc574a551 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemToWorkItem.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ReadWrite/WorkItemToWorkItem.cs
@@ -7,6 +7,6 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ReadWrite;
 [NoResource]
 public sealed class WorkItemToWorkItem
 {
-    public WorkItem FromItem { get; set; } = null!;
-    public WorkItem ToItem { get; set; } = null!;
+    public required WorkItem FromItem { get; set; }
+    public required WorkItem ToItem { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Customer.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Customer.cs
index 952eed4e1f..e4fad311c1 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Customer.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Customer.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.RequiredRelationships;
 public sealed class Customer : Identifiable<long>
 {
     [Attr]
-    public string EmailAddress { get; set; } = null!;
+    public required string EmailAddress { get; set; }
 
     [HasMany]
     public ISet<Order> Orders { get; set; } = new HashSet<Order>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Order.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Order.cs
index 390556bf9f..e4226257cf 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Order.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Order.cs
@@ -12,8 +12,8 @@ public sealed class Order : Identifiable<long>
     public decimal Amount { get; set; }
 
     [HasOne]
-    public Customer Customer { get; set; } = null!;
+    public required Customer Customer { get; set; }
 
     [HasOne]
-    public Shipment Shipment { get; set; } = null!;
+    public required Shipment Shipment { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Shipment.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Shipment.cs
index ed14d0a946..8d6242b284 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Shipment.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/RequiredRelationships/Shipment.cs
@@ -11,11 +11,11 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.RequiredRelationships;
 public sealed class Shipment : Identifiable<long>
 {
     [Attr]
-    public string TrackAndTraceCode { get; set; } = null!;
+    public required string TrackAndTraceCode { get; set; }
 
     [Attr]
     public DateTimeOffset ShippedAt { get; set; }
 
     [HasOne]
-    public Order Order { get; set; } = null!;
+    public required Order Order { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/InjectionFakers.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/InjectionFakers.cs
index fc6cda269a..6db1321c55 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/InjectionFakers.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/InjectionFakers.cs
@@ -28,8 +28,10 @@ public InjectionFakers(IServiceProvider serviceProvider)
 
         _lazyPostOfficeFaker = new Lazy<Faker<PostOffice>>(() => new Faker<PostOffice>()
             .MakeDeterministic(systemTimeUtc)
-            .CustomInstantiator(_ => new PostOffice(ResolveDbContext()))
-            .RuleFor(postOffice => postOffice.Address, faker => faker.Address.FullAddress()));
+            .CustomInstantiator(faker => new PostOffice(ResolveDbContext())
+            {
+                Address = faker.Address.FullAddress()
+            }));
 
         _lazyGiftCertificateFaker = new Lazy<Faker<GiftCertificate>>(() => new Faker<GiftCertificate>()
             .MakeDeterministic(systemTimeUtc)
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/PostOffice.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/PostOffice.cs
index ef91b2b1a6..70b3f4bb01 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/PostOffice.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceConstructorInjection/PostOffice.cs
@@ -12,7 +12,7 @@ public sealed class PostOffice(InjectionDbContext injectionDbContext) : Identifi
     private readonly TimeProvider _timeProvider = injectionDbContext.TimeProvider;
 
     [Attr]
-    public string Address { get; set; } = null!;
+    public required string Address { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowView)]
     [NotMapped]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Constellation.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Constellation.cs
index 72bd00a662..8b60a25fe1 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Constellation.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Constellation.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceDefinitions.Reading;
 public sealed class Constellation : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     [Required]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Moon.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Moon.cs
index 3ce6cde44c..84b4ccef7c 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Moon.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Moon.cs
@@ -9,13 +9,13 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceDefinitions.Reading;
 public sealed class Moon : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public decimal SolarRadius { get; set; }
 
     [HasOne]
-    public Planet OrbitsAround { get; set; } = null!;
+    public required Planet OrbitsAround { get; set; }
 
     [HasOne]
     public Star? IsGivenLightBy { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Planet.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Planet.cs
index 33a5fe1081..e41905eaa8 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Planet.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Planet.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceDefinitions.Reading;
 public sealed class Planet : Identifiable<long>
 {
     [Attr]
-    public string PublicName { get; set; } = null!;
+    public required string PublicName { get; set; }
 
     [Attr]
     public string? PrivateName { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Star.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Star.cs
index 48bc6f0e44..d1bdf69f1d 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Star.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Reading/Star.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceDefinitions.Reading;
 public sealed class Star : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public StarKind Kind { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Scholarship.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Scholarship.cs
index a5a75eb939..4db5f82dfe 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Scholarship.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Scholarship.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceDefinitions.Serializat
 public sealed class Scholarship : Identifiable<long>
 {
     [Attr]
-    public string ProgramName { get; set; } = null!;
+    public required string ProgramName { get; set; }
 
     [Attr]
     public decimal Amount { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Student.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Student.cs
index fa20cb05c6..e2c544310a 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Student.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceDefinitions/Serialization/Student.cs
@@ -9,10 +9,10 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceDefinitions.Serializat
 public sealed class Student : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
-    public string SocialSecurityNumber { get; set; } = null!;
+    public required string SocialSecurityNumber { get; set; }
 
     [HasOne]
     public Scholarship? Scholarship { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/BicycleLight.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/BicycleLight.cs
index f1d41f44af..e84c05b3d1 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/BicycleLight.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/BicycleLight.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public sealed class BicycleLight : Identifiable<long>
 {
     [Attr]
-    public string Color { get; set; } = null!;
+    public required string Color { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericFeature.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericFeature.cs
index 79de2d858e..1e34065aed 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericFeature.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericFeature.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public sealed class GenericFeature : Identifiable<long>
 {
     [Attr]
-    public string Description { get; set; } = null!;
+    public required string Description { get; set; }
 
     [HasMany]
     public ISet<GenericProperty> Properties { get; set; } = new HashSet<GenericProperty>();
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericProperty.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericProperty.cs
index e410b9a803..1c188a02e7 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericProperty.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/GenericProperty.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public abstract class GenericProperty : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/MotorVehicle.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/MotorVehicle.cs
index 2578d5d128..07170c6770 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/MotorVehicle.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/MotorVehicle.cs
@@ -11,10 +11,10 @@ public abstract class MotorVehicle : Vehicle
     public override bool RequiresDriverLicense { get; set; }
 
     [Attr]
-    public string LicensePlate { get; set; } = null!;
+    public required string LicensePlate { get; set; }
 
     [HasOne]
-    public Engine Engine { get; set; } = null!;
+    public required Engine Engine { get; set; }
 
     [HasOne]
     public NavigationSystem? NavigationSystem { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NavigationSystem.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NavigationSystem.cs
index 015c1089c7..64d67f8e8b 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NavigationSystem.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NavigationSystem.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public sealed class NavigationSystem : Identifiable<long>
 {
     [Attr]
-    public string ModelType { get; set; } = null!;
+    public required string ModelType { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NumberProperty.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NumberProperty.cs
index e3d924f206..49c9978c8d 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NumberProperty.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/NumberProperty.cs
@@ -8,5 +8,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public sealed class NumberProperty : GenericProperty
 {
     [HasOne]
-    public NumberValue Value { get; set; } = null!;
+    public required NumberValue Value { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringProperty.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringProperty.cs
index a145d17978..13f33b10f5 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringProperty.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringProperty.cs
@@ -8,5 +8,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public sealed class StringProperty : GenericProperty
 {
     [HasOne]
-    public StringValue Value { get; set; } = null!;
+    public required StringValue Value { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringValue.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringValue.cs
index fc620f7bd2..e620d71f1b 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringValue.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ResourceInheritance/Models/StringValue.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ResourceInheritance.Models;
 public sealed class StringValue : Identifiable<long>
 {
     [Attr]
-    public string Content { get; set; } = null!;
+    public required string Content { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/RestrictedControllers/Pillow.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/RestrictedControllers/Pillow.cs
index 221555555f..bd78207bb5 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/RestrictedControllers/Pillow.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/RestrictedControllers/Pillow.cs
@@ -9,5 +9,5 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.RestrictedControllers;
 public sealed class Pillow : Identifiable<long>
 {
     [Attr]
-    public string Color { get; set; } = null!;
+    public required string Color { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Address.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Address.cs
index 97017706e0..45c9763762 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Address.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Address.cs
@@ -5,8 +5,8 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Serialization;
 [UsedImplicitly(ImplicitUseTargetFlags.Members)]
 public sealed class Address
 {
-    public string Street { get; set; } = null!;
+    public required string Street { get; set; }
     public string? ZipCode { get; set; }
-    public string City { get; set; } = null!;
-    public string Country { get; set; } = null!;
+    public required string City { get; set; }
+    public required string Country { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Meeting.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Meeting.cs
index f7599f6f01..0880d84e10 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Meeting.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/Meeting.cs
@@ -12,7 +12,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Serialization;
 public sealed class Meeting : Identifiable<Guid>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     public DateTimeOffset StartTime { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/MeetingAttendee.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/MeetingAttendee.cs
index 118e0c9df5..1351ed4ef3 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/MeetingAttendee.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/Serialization/MeetingAttendee.cs
@@ -9,10 +9,10 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.Serialization;
 public sealed class MeetingAttendee : Identifiable<Guid>
 {
     [Attr]
-    public string DisplayName { get; set; } = null!;
+    public required string DisplayName { get; set; }
 
     [Attr]
-    public Address HomeAddress { get; set; } = null!;
+    public required Address HomeAddress { get; set; }
 
     [HasOne]
     public Meeting? Meeting { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Company.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Company.cs
index d1ea71a8d8..03edc14321 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Company.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Company.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.SoftDeletion;
 public sealed class Company : Identifiable<long>, ISoftDeletable
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     public DateTimeOffset? SoftDeletedAt { get; set; }
 
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Department.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Department.cs
index f006ff015d..1ab79ccdde 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Department.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/SoftDeletion/Department.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.SoftDeletion;
 public sealed class Department : Identifiable<long>, ISoftDeletable
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     public DateTimeOffset? SoftDeletedAt { get; set; }
 
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Game.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Game.cs
index a983c66d7b..9a7af8d98c 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Game.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Game.cs
@@ -11,7 +11,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ZeroKeys;
 public sealed class Game : Identifiable<int?>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     [NotMapped]
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Map.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Map.cs
index c8226a4009..25b7253fb8 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Map.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Map.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ZeroKeys;
 public sealed class Map : Identifiable<Guid?>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasOne]
     public Game? Game { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Player.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Player.cs
index 52f52d112c..ea6a2b6cf6 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Player.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ZeroKeys/Player.cs
@@ -10,7 +10,7 @@ namespace JsonApiDotNetCoreTests.IntegrationTests.ZeroKeys;
 public sealed class Player : Identifiable<string?>
 {
     [Attr]
-    public string EmailAddress { get; set; } = null!;
+    public required string EmailAddress { get; set; }
 
     [HasOne]
     public Game? ActiveGame { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/FieldChains/FieldChainPatternInheritanceMatchTests.cs b/test/JsonApiDotNetCoreTests/UnitTests/FieldChains/FieldChainPatternInheritanceMatchTests.cs
index f5cd78f6ff..915a742bd2 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/FieldChains/FieldChainPatternInheritanceMatchTests.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/FieldChains/FieldChainPatternInheritanceMatchTests.cs
@@ -173,7 +173,7 @@ private abstract class Base : Identifiable<long>
         public string? Value { get; set; }
 
         [HasOne]
-        public Base SingleItem { get; set; } = null!;
+        public required Base SingleItem { get; set; }
 
         [HasMany]
         public ISet<Base> SetOfItems { get; set; } = new HashSet<Base>();
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/ModelStateValidation/ModelStateValidationTests.cs b/test/JsonApiDotNetCoreTests/UnitTests/ModelStateValidation/ModelStateValidationTests.cs
index 17a62b3de3..d494eaa86f 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/ModelStateValidation/ModelStateValidationTests.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/ModelStateValidation/ModelStateValidationTests.cs
@@ -118,13 +118,13 @@ private sealed class Parent : Identifiable<long>
         public ComplexObject? ComplexObject { get; set; }
 
         [Attr(PublicName = "publicNameOfComplexList")]
-        public IList<ComplexObject> ComplexList { get; set; } = null!;
+        public required IList<ComplexObject> ComplexList { get; set; }
 
         [HasOne(PublicName = "publicNameOfPrimaryChild")]
         public Child? PrimaryChild { get; set; }
 
         [HasMany(PublicName = "publicNameOfChildren")]
-        public ISet<Child> Children { get; set; } = null!;
+        public required ISet<Child> Children { get; set; }
     }
 
     [UsedImplicitly(ImplicitUseTargetFlags.Members)]
@@ -149,6 +149,6 @@ private sealed class ComplexObject
         public ComplexObject? ParentObject { get; set; }
 
         [JsonPropertyName("jsonElements")]
-        public IList<ComplexObject> Elements { get; set; } = null!;
+        public required IList<ComplexObject> Elements { get; set; }
     }
 }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/ResourceDefinitions/CreateSortExpressionFromLambdaTests.cs b/test/JsonApiDotNetCoreTests/UnitTests/ResourceDefinitions/CreateSortExpressionFromLambdaTests.cs
index dc59dbe907..fae2e9addd 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/ResourceDefinitions/CreateSortExpressionFromLambdaTests.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/ResourceDefinitions/CreateSortExpressionFromLambdaTests.cs
@@ -358,10 +358,10 @@ public SortExpression GetSortExpressionFromLambda(PropertySortOrder sortOrder)
     private abstract class FileSystemEntry : Identifiable<long>
     {
         [Attr]
-        public string Name { get; set; } = null!;
+        public required string Name { get; set; }
 
         [HasOne]
-        public FileSystemEntry Parent { get; set; } = null!;
+        public required FileSystemEntry Parent { get; set; }
 
         [HasMany]
         public List<FileSystemEntry> Children { get; set; } = [];
@@ -381,7 +381,7 @@ private sealed class DirectoryEntry : FileSystemEntry
     private sealed class FileEntry : FileSystemEntry
     {
         [Attr]
-        public string Content { get; set; } = null!;
+        public required string Content { get; set; }
 
         [Attr]
         public ulong Length { get; set; }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Article.cs b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Article.cs
index dfb556bab3..236651abaf 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Article.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Article.cs
@@ -8,11 +8,11 @@ namespace JsonApiDotNetCoreTests.UnitTests.Serialization.Response.Models;
 public sealed class Article : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [HasOne]
     public Person? Reviewer { get; set; }
 
     [HasOne]
-    public Person Author { get; set; } = null!;
+    public required Person Author { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Blog.cs b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Blog.cs
index 55d75af2fa..8096676d4b 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Blog.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Blog.cs
@@ -8,11 +8,11 @@ namespace JsonApiDotNetCoreTests.UnitTests.Serialization.Response.Models;
 public sealed class Blog : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [HasOne]
-    public Person Reviewer { get; set; } = null!;
+    public required Person Reviewer { get; set; }
 
     [HasOne]
-    public Person Author { get; set; } = null!;
+    public required Person Author { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Food.cs b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Food.cs
index 3a06c037d7..1f966a99e8 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Food.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Food.cs
@@ -8,5 +8,5 @@ namespace JsonApiDotNetCoreTests.UnitTests.Serialization.Response.Models;
 public sealed class Food : Identifiable<long>
 {
     [Attr]
-    public string Dish { get; set; } = null!;
+    public required string Dish { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Person.cs b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Person.cs
index a5b86ed950..7d8fd5eb0f 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Person.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Person.cs
@@ -8,14 +8,14 @@ namespace JsonApiDotNetCoreTests.UnitTests.Serialization.Response.Models;
 public sealed class Person : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<Blog> Blogs { get; set; } = new HashSet<Blog>();
 
     [HasOne]
-    public Food FavoriteFood { get; set; } = null!;
+    public required Food FavoriteFood { get; set; }
 
     [HasOne]
-    public Song FavoriteSong { get; set; } = null!;
+    public required Song FavoriteSong { get; set; }
 }
diff --git a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Song.cs b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Song.cs
index b9822f95a0..ab1e9e6c81 100644
--- a/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Song.cs
+++ b/test/JsonApiDotNetCoreTests/UnitTests/Serialization/Response/Models/Song.cs
@@ -8,5 +8,5 @@ namespace JsonApiDotNetCoreTests.UnitTests.Serialization.Response.Models;
 public sealed class Song : Identifiable<long>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 }
diff --git a/test/OpenApiTests/AtomicOperations/Course.cs b/test/OpenApiTests/AtomicOperations/Course.cs
index de193c6893..9d5c6deea8 100644
--- a/test/OpenApiTests/AtomicOperations/Course.cs
+++ b/test/OpenApiTests/AtomicOperations/Course.cs
@@ -12,7 +12,7 @@ namespace OpenApiTests.AtomicOperations;
 public sealed class Course : Identifiable<Guid>
 {
     [Attr]
-    public string Subject { get; set; } = null!;
+    public required string Subject { get; set; }
 
     [Attr]
     public string? Description { get; set; }
diff --git a/test/OpenApiTests/AtomicOperations/Enrollment.cs b/test/OpenApiTests/AtomicOperations/Enrollment.cs
index c89cf2537c..977b2d56f9 100644
--- a/test/OpenApiTests/AtomicOperations/Enrollment.cs
+++ b/test/OpenApiTests/AtomicOperations/Enrollment.cs
@@ -22,8 +22,8 @@ public sealed class Enrollment(OperationsDbContext dbContext) : Identifiable<lon
     public bool HasGraduated => GraduatedAt != null && GraduatedAt <= Today;
 
     [HasOne]
-    public Student Student { get; set; } = null!;
+    public required Student Student { get; set; }
 
     [HasOne]
-    public Course Course { get; set; } = null!;
+    public required Course Course { get; set; }
 }
diff --git a/test/OpenApiTests/AtomicOperations/OperationsFakers.cs b/test/OpenApiTests/AtomicOperations/OperationsFakers.cs
index c77e045faa..8f08e42d08 100644
--- a/test/OpenApiTests/AtomicOperations/OperationsFakers.cs
+++ b/test/OpenApiTests/AtomicOperations/OperationsFakers.cs
@@ -13,8 +13,11 @@ public sealed class OperationsFakers
 {
     private readonly Lazy<Faker<Course>> _lazyCourseFaker = new(() => new Faker<Course>()
         .MakeDeterministic()
-        .RuleFor(course => course.Subject, faker => faker.Lorem.Word())
-        .RuleFor(course => course.Description, faker => faker.Lorem.Sentence()));
+        .CustomInstantiator(faker => new Course
+        {
+            Subject = faker.Lorem.Word(),
+            Description = faker.Lorem.Sentence()
+        }));
 
     private readonly Lazy<Faker<Teacher>> _lazyTeacherFaker = new(() => new Faker<Teacher>()
         .MakeDeterministic()
@@ -23,8 +26,11 @@ public sealed class OperationsFakers
 
     private readonly Lazy<Faker<Student>> _lazyStudentFaker = new(() => new Faker<Student>()
         .MakeDeterministic()
-        .RuleFor(student => student.Name, faker => faker.Person.FullName)
-        .RuleFor(student => student.EmailAddress, faker => faker.Person.Email));
+        .CustomInstantiator(faker => new Student
+        {
+            Name = faker.Person.FullName,
+            EmailAddress = faker.Person.Email
+        }));
 
     private readonly Lazy<Faker<Enrollment>> _lazyEnrollmentFaker;
 
@@ -37,9 +43,24 @@ public OperationsFakers(IServiceProvider serviceProvider)
     {
         _lazyEnrollmentFaker = new Lazy<Faker<Enrollment>>(() => new Faker<Enrollment>()
             .MakeDeterministic()
-            .CustomInstantiator(_ => new Enrollment(ResolveDbContext(serviceProvider)))
-            .RuleFor(enrollment => enrollment.EnrolledAt, faker => faker.Date.PastDateOnly())
-            .RuleFor(enrollment => enrollment.GraduatedAt, faker => faker.Date.RecentDateOnly()));
+            .CustomInstantiator(faker =>
+            {
+                OperationsDbContext dbContext = ResolveDbContext(serviceProvider);
+
+                return new Enrollment(dbContext)
+                {
+                    Student = new Student
+                    {
+                        Name = faker.Name.FullName()
+                    },
+                    Course = new Course
+                    {
+                        Subject = faker.Commerce.Department()
+                    },
+                    EnrolledAt = faker.Date.PastDateOnly(),
+                    GraduatedAt = faker.Date.RecentDateOnly()
+                };
+            }));
     }
 
     private OperationsDbContext ResolveDbContext(IServiceProvider serviceProvider)
diff --git a/test/OpenApiTests/AtomicOperations/Student.cs b/test/OpenApiTests/AtomicOperations/Student.cs
index 465fa52bc0..613919a432 100644
--- a/test/OpenApiTests/AtomicOperations/Student.cs
+++ b/test/OpenApiTests/AtomicOperations/Student.cs
@@ -10,7 +10,7 @@ namespace OpenApiTests.AtomicOperations;
 public sealed class Student : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? EmailAddress { get; set; }
diff --git a/test/OpenApiTests/AtomicOperations/Teacher.cs b/test/OpenApiTests/AtomicOperations/Teacher.cs
index 86ff5bb4d4..c7995a287d 100644
--- a/test/OpenApiTests/AtomicOperations/Teacher.cs
+++ b/test/OpenApiTests/AtomicOperations/Teacher.cs
@@ -9,7 +9,7 @@ namespace OpenApiTests.AtomicOperations;
 public sealed class Teacher : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? EmailAddress { get; set; }
diff --git a/test/OpenApiTests/ClientIdGenerationModes/Game.cs b/test/OpenApiTests/ClientIdGenerationModes/Game.cs
index c4880054c1..243b2be6e8 100644
--- a/test/OpenApiTests/ClientIdGenerationModes/Game.cs
+++ b/test/OpenApiTests/ClientIdGenerationModes/Game.cs
@@ -12,7 +12,7 @@ namespace OpenApiTests.ClientIdGenerationModes;
 public sealed class Game : Identifiable<Guid>
 {
     [Attr]
-    public string Title { get; set; } = null!;
+    public required string Title { get; set; }
 
     [Attr]
     public decimal PurchasePrice { get; set; }
diff --git a/test/OpenApiTests/ClientIdGenerationModes/Player.cs b/test/OpenApiTests/ClientIdGenerationModes/Player.cs
index e150af5756..d121039bf3 100644
--- a/test/OpenApiTests/ClientIdGenerationModes/Player.cs
+++ b/test/OpenApiTests/ClientIdGenerationModes/Player.cs
@@ -12,7 +12,7 @@ namespace OpenApiTests.ClientIdGenerationModes;
 public sealed class Player : Identifiable<Guid>
 {
     [Attr]
-    public string UserName { get; set; } = null!;
+    public required string UserName { get; set; }
 
     [HasMany]
     public List<Game> OwnedGames { get; set; } = [];
diff --git a/test/OpenApiTests/ClientIdGenerationModes/PlayerGroup.cs b/test/OpenApiTests/ClientIdGenerationModes/PlayerGroup.cs
index 9f2547a61f..925f4a99ba 100644
--- a/test/OpenApiTests/ClientIdGenerationModes/PlayerGroup.cs
+++ b/test/OpenApiTests/ClientIdGenerationModes/PlayerGroup.cs
@@ -12,7 +12,7 @@ namespace OpenApiTests.ClientIdGenerationModes;
 public sealed class PlayerGroup : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public List<Player> Players { get; set; } = [];
diff --git a/test/OpenApiTests/Documentation/Elevator.cs b/test/OpenApiTests/Documentation/Elevator.cs
index c739454c55..dc7de07842 100644
--- a/test/OpenApiTests/Documentation/Elevator.cs
+++ b/test/OpenApiTests/Documentation/Elevator.cs
@@ -22,5 +22,5 @@ public sealed class Elevator : Identifiable<long>
     /// The skyscraper this elevator exists in.
     /// </summary>
     [HasOne]
-    public Skyscraper ExistsIn { get; set; } = null!;
+    public required Skyscraper ExistsIn { get; set; }
 }
diff --git a/test/OpenApiTests/Documentation/Space.cs b/test/OpenApiTests/Documentation/Space.cs
index 196780dd34..61f3e663db 100644
--- a/test/OpenApiTests/Documentation/Space.cs
+++ b/test/OpenApiTests/Documentation/Space.cs
@@ -27,5 +27,5 @@ public sealed class Space : Identifiable<long>
     /// The skyscraper this space exists in.
     /// </summary>
     [HasOne]
-    public Skyscraper ExistsIn { get; set; } = null!;
+    public required Skyscraper ExistsIn { get; set; }
 }
diff --git a/test/OpenApiTests/Headers/Country.cs b/test/OpenApiTests/Headers/Country.cs
index a0398c03bc..cc38c2c444 100644
--- a/test/OpenApiTests/Headers/Country.cs
+++ b/test/OpenApiTests/Headers/Country.cs
@@ -9,7 +9,7 @@ namespace OpenApiTests.Headers;
 public sealed class Country : Identifiable<Guid>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public long Population { get; set; }
diff --git a/test/OpenApiTests/Headers/Language.cs b/test/OpenApiTests/Headers/Language.cs
index 3f2eae5ff3..cd43fa5f5d 100644
--- a/test/OpenApiTests/Headers/Language.cs
+++ b/test/OpenApiTests/Headers/Language.cs
@@ -9,8 +9,8 @@ namespace OpenApiTests.Headers;
 public sealed class Language : Identifiable<Guid>
 {
     [Attr]
-    public string Code { get; set; } = null!;
+    public required string Code { get; set; }
 
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 }
diff --git a/test/OpenApiTests/IdObfuscation/BankAccount.cs b/test/OpenApiTests/IdObfuscation/BankAccount.cs
index 319b025856..9456c3351f 100644
--- a/test/OpenApiTests/IdObfuscation/BankAccount.cs
+++ b/test/OpenApiTests/IdObfuscation/BankAccount.cs
@@ -9,7 +9,7 @@ namespace OpenApiTests.IdObfuscation;
 public sealed class BankAccount : ObfuscatedIdentifiable
 {
     [Attr]
-    public string Iban { get; set; } = null!;
+    public required string Iban { get; set; }
 
     [HasMany]
     public IList<DebitCard> Cards { get; set; } = new List<DebitCard>();
diff --git a/test/OpenApiTests/IdObfuscation/DebitCard.cs b/test/OpenApiTests/IdObfuscation/DebitCard.cs
index 7bbdb26a8e..694478f39e 100644
--- a/test/OpenApiTests/IdObfuscation/DebitCard.cs
+++ b/test/OpenApiTests/IdObfuscation/DebitCard.cs
@@ -9,11 +9,11 @@ namespace OpenApiTests.IdObfuscation;
 public sealed class DebitCard : ObfuscatedIdentifiable
 {
     [Attr]
-    public string OwnerName { get; set; } = null!;
+    public required string OwnerName { get; set; }
 
     [Attr]
     public short PinCode { get; set; }
 
     [HasOne]
-    public BankAccount Account { get; set; } = null!;
+    public required BankAccount Account { get; set; }
 }
diff --git a/test/OpenApiTests/LegacyOpenApi/Airplane.cs b/test/OpenApiTests/LegacyOpenApi/Airplane.cs
index aa89d99f61..df270b1243 100644
--- a/test/OpenApiTests/LegacyOpenApi/Airplane.cs
+++ b/test/OpenApiTests/LegacyOpenApi/Airplane.cs
@@ -11,7 +11,7 @@ public sealed class Airplane : Identifiable<string>
 {
     [Attr(Capabilities = AttrCapabilities.AllowView | AttrCapabilities.AllowCreate | AttrCapabilities.AllowChange)]
     [MaxLength(255)]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowView | AttrCapabilities.AllowCreate | AttrCapabilities.AllowChange)]
     [MaxLength(16)]
diff --git a/test/OpenApiTests/LegacyOpenApi/Flight.cs b/test/OpenApiTests/LegacyOpenApi/Flight.cs
index 5baa315523..36e0a747cf 100644
--- a/test/OpenApiTests/LegacyOpenApi/Flight.cs
+++ b/test/OpenApiTests/LegacyOpenApi/Flight.cs
@@ -12,7 +12,7 @@ public sealed class Flight : Identifiable<string>
 {
     [Attr(Capabilities = AttrCapabilities.AllowView | AttrCapabilities.AllowChange)]
     [MaxLength(40)]
-    public string FinalDestination { get; set; } = null!;
+    public required string FinalDestination { get; set; }
 
     [Attr(Capabilities = AttrCapabilities.AllowView | AttrCapabilities.AllowChange)]
     [MaxLength(2000)]
@@ -31,7 +31,7 @@ public sealed class Flight : Identifiable<string>
     public ISet<FlightAttendant> CabinCrewMembers { get; set; } = new HashSet<FlightAttendant>();
 
     [HasOne]
-    public FlightAttendant Purser { get; set; } = null!;
+    public required FlightAttendant Purser { get; set; }
 
     [HasOne]
     public FlightAttendant? BackupPurser { get; set; }
diff --git a/test/OpenApiTests/LegacyOpenApi/FlightAttendant.cs b/test/OpenApiTests/LegacyOpenApi/FlightAttendant.cs
index 6eb6872072..497c5034a0 100644
--- a/test/OpenApiTests/LegacyOpenApi/FlightAttendant.cs
+++ b/test/OpenApiTests/LegacyOpenApi/FlightAttendant.cs
@@ -26,7 +26,7 @@ public sealed class FlightAttendant : Identifiable<string>
 
     [Attr(Capabilities = AttrCapabilities.AllowView | AttrCapabilities.AllowCreate)]
     [Url]
-    public string ProfileImageUrl { get; set; } = null!;
+    public required string ProfileImageUrl { get; set; }
 
     [Attr]
     public long DistanceTraveledInKilometers { get; set; }
diff --git a/test/OpenApiTests/LegacyOpenApi/Passenger.cs b/test/OpenApiTests/LegacyOpenApi/Passenger.cs
index c939562447..f345f10e0d 100644
--- a/test/OpenApiTests/LegacyOpenApi/Passenger.cs
+++ b/test/OpenApiTests/LegacyOpenApi/Passenger.cs
@@ -11,7 +11,7 @@ public sealed class Passenger : Identifiable<string>
 {
     [Attr(PublicName = "document-number", Capabilities = AttrCapabilities.AllowCreate | AttrCapabilities.AllowChange)]
     [MaxLength(9)]
-    public string PassportNumber { get; set; } = null!;
+    public required string PassportNumber { get; set; }
 
     [Attr]
     public string? FullName { get; set; }
diff --git a/test/OpenApiTests/Links/Accommodation.cs b/test/OpenApiTests/Links/Accommodation.cs
index 5a793da701..42e4ecb6b9 100644
--- a/test/OpenApiTests/Links/Accommodation.cs
+++ b/test/OpenApiTests/Links/Accommodation.cs
@@ -9,5 +9,5 @@ namespace OpenApiTests.Links;
 public sealed class Accommodation : Identifiable<long>
 {
     [Attr]
-    public string Address { get; set; } = null!;
+    public required string Address { get; set; }
 }
diff --git a/test/OpenApiTests/Links/Excursion.cs b/test/OpenApiTests/Links/Excursion.cs
index 92143cab73..29add4bc5d 100644
--- a/test/OpenApiTests/Links/Excursion.cs
+++ b/test/OpenApiTests/Links/Excursion.cs
@@ -14,5 +14,5 @@ public sealed class Excursion : Identifiable<long>
     public DateTime? OccursAt { get; set; }
 
     [Attr]
-    public string Description { get; set; } = null!;
+    public required string Description { get; set; }
 }
diff --git a/test/OpenApiTests/Links/Vacation.cs b/test/OpenApiTests/Links/Vacation.cs
index df592a4423..130b9eb5da 100644
--- a/test/OpenApiTests/Links/Vacation.cs
+++ b/test/OpenApiTests/Links/Vacation.cs
@@ -18,7 +18,7 @@ public sealed class Vacation : Identifiable<long>
     public DateTime? EndsAt { get; set; }
 
     [HasOne]
-    public Accommodation Accommodation { get; set; } = null!;
+    public required Accommodation Accommodation { get; set; }
 
     [HasOne]
     public Transport? Transport { get; set; }
diff --git a/test/OpenApiTests/ModelStateValidation/SocialMediaAccount.cs b/test/OpenApiTests/ModelStateValidation/SocialMediaAccount.cs
index 28fbd7148d..ed167a1a47 100644
--- a/test/OpenApiTests/ModelStateValidation/SocialMediaAccount.cs
+++ b/test/OpenApiTests/ModelStateValidation/SocialMediaAccount.cs
@@ -25,7 +25,7 @@ public sealed class SocialMediaAccount : Identifiable<Guid>
 
     [Attr]
     [Required(AllowEmptyStrings = true)]
-    public string LastName { get; set; } = null!;
+    public required string LastName { get; set; }
 
     [Attr]
     [StringLength(18, MinimumLength = 3)]
diff --git a/test/OpenApiTests/NamingConventions/StaffMember.cs b/test/OpenApiTests/NamingConventions/StaffMember.cs
index beeeb3f997..ff5c3bf9a3 100644
--- a/test/OpenApiTests/NamingConventions/StaffMember.cs
+++ b/test/OpenApiTests/NamingConventions/StaffMember.cs
@@ -9,7 +9,7 @@ namespace OpenApiTests.NamingConventions;
 public sealed class StaffMember : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public int Age { get; set; }
diff --git a/test/OpenApiTests/NamingConventions/Supermarket.cs b/test/OpenApiTests/NamingConventions/Supermarket.cs
index ea7a2cb8c4..39efa3f8d8 100644
--- a/test/OpenApiTests/NamingConventions/Supermarket.cs
+++ b/test/OpenApiTests/NamingConventions/Supermarket.cs
@@ -9,13 +9,13 @@ namespace OpenApiTests.NamingConventions;
 public sealed class Supermarket : Identifiable<long>
 {
     [Attr]
-    public string NameOfCity { get; set; } = null!;
+    public required string NameOfCity { get; set; }
 
     [Attr]
     public SupermarketType Kind { get; set; }
 
     [HasOne]
-    public StaffMember StoreManager { get; set; } = null!;
+    public required StaffMember StoreManager { get; set; }
 
     [HasOne]
     public StaffMember? BackupStoreManager { get; set; }
diff --git a/test/OpenApiTests/QueryStrings/NameValuePair.cs b/test/OpenApiTests/QueryStrings/NameValuePair.cs
index ab7fd2f61e..a927920a13 100644
--- a/test/OpenApiTests/QueryStrings/NameValuePair.cs
+++ b/test/OpenApiTests/QueryStrings/NameValuePair.cs
@@ -9,11 +9,11 @@ namespace OpenApiTests.QueryStrings;
 public sealed class NameValuePair : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? Value { get; set; }
 
     [HasOne]
-    public Node Owner { get; set; } = null!;
+    public required Node Owner { get; set; }
 }
diff --git a/test/OpenApiTests/QueryStrings/Node.cs b/test/OpenApiTests/QueryStrings/Node.cs
index e9da915295..9ea72c7b9d 100644
--- a/test/OpenApiTests/QueryStrings/Node.cs
+++ b/test/OpenApiTests/QueryStrings/Node.cs
@@ -9,7 +9,7 @@ namespace OpenApiTests.QueryStrings;
 public sealed class Node : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [Attr]
     public string? Comment { get; set; }
diff --git a/test/OpenApiTests/ResourceFieldValidation/NullableReferenceTypesOn/NrtOnResource.cs b/test/OpenApiTests/ResourceFieldValidation/NullableReferenceTypesOn/NrtOnResource.cs
index 69056d716a..4022d6bdd1 100644
--- a/test/OpenApiTests/ResourceFieldValidation/NullableReferenceTypesOn/NrtOnResource.cs
+++ b/test/OpenApiTests/ResourceFieldValidation/NullableReferenceTypesOn/NrtOnResource.cs
@@ -10,11 +10,11 @@ namespace OpenApiTests.ResourceFieldValidation.NullableReferenceTypesOn;
 public sealed class NrtOnResource : Identifiable<long>
 {
     [Attr]
-    public string NonNullableReferenceType { get; set; } = null!;
+    public required string NonNullableReferenceType { get; set; }
 
     [Attr]
     [Required]
-    public string RequiredNonNullableReferenceType { get; set; } = null!;
+    public required string RequiredNonNullableReferenceType { get; set; }
 
     [Attr]
     public string? NullableReferenceType { get; set; }
@@ -38,11 +38,11 @@ public sealed class NrtOnResource : Identifiable<long>
     public int? RequiredNullableValueType { get; set; }
 
     [HasOne]
-    public NrtOnEmpty NonNullableToOne { get; set; } = null!;
+    public required NrtOnEmpty NonNullableToOne { get; set; }
 
     [Required]
     [HasOne]
-    public NrtOnEmpty RequiredNonNullableToOne { get; set; } = null!;
+    public required NrtOnEmpty RequiredNonNullableToOne { get; set; }
 
     [HasOne]
     public NrtOnEmpty? NullableToOne { get; set; }
diff --git a/test/OpenApiTests/ResourceInheritance/Models/District.cs b/test/OpenApiTests/ResourceInheritance/Models/District.cs
index 3ef752e386..d826c84cc6 100644
--- a/test/OpenApiTests/ResourceInheritance/Models/District.cs
+++ b/test/OpenApiTests/ResourceInheritance/Models/District.cs
@@ -9,7 +9,7 @@ namespace OpenApiTests.ResourceInheritance.Models;
 public sealed class District : Identifiable<Guid>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 
     [HasMany]
     public ISet<Building> Buildings { get; set; } = new HashSet<Building>();
diff --git a/test/OpenApiTests/ResourceInheritance/Models/Mansion.cs b/test/OpenApiTests/ResourceInheritance/Models/Mansion.cs
index acf87c8eee..cd9bcbc7b1 100644
--- a/test/OpenApiTests/ResourceInheritance/Models/Mansion.cs
+++ b/test/OpenApiTests/ResourceInheritance/Models/Mansion.cs
@@ -8,7 +8,7 @@ namespace OpenApiTests.ResourceInheritance.Models;
 public sealed class Mansion : Residence
 {
     [Attr]
-    public string OwnerName { get; set; } = null!;
+    public required string OwnerName { get; set; }
 
     [HasMany]
     public ISet<StaffMember> Staff { get; set; } = new HashSet<StaffMember>();
diff --git a/test/OpenApiTests/ResourceInheritance/Models/Room.cs b/test/OpenApiTests/ResourceInheritance/Models/Room.cs
index 6cf38598b7..cb25ecdaad 100644
--- a/test/OpenApiTests/ResourceInheritance/Models/Room.cs
+++ b/test/OpenApiTests/ResourceInheritance/Models/Room.cs
@@ -14,5 +14,5 @@ public abstract class Room : Identifiable<long>
     public int? SurfaceInSquareMeters { get; set; }
 
     [HasOne]
-    public Residence Residence { get; set; } = null!;
+    public required Residence Residence { get; set; }
 }
diff --git a/test/OpenApiTests/ResourceInheritance/Models/StaffMember.cs b/test/OpenApiTests/ResourceInheritance/Models/StaffMember.cs
index 0baa95db7e..1015891b43 100644
--- a/test/OpenApiTests/ResourceInheritance/Models/StaffMember.cs
+++ b/test/OpenApiTests/ResourceInheritance/Models/StaffMember.cs
@@ -9,5 +9,5 @@ namespace OpenApiTests.ResourceInheritance.Models;
 public sealed class StaffMember : Identifiable<long>
 {
     [Attr]
-    public string Name { get; set; } = null!;
+    public required string Name { get; set; }
 }
diff --git a/test/OpenApiTests/RestrictedControllers/Channel.cs b/test/OpenApiTests/RestrictedControllers/Channel.cs
index a91555582d..9fa050de66 100644
--- a/test/OpenApiTests/RestrictedControllers/Channel.cs
+++ b/test/OpenApiTests/RestrictedControllers/Channel.cs
@@ -17,7 +17,7 @@ public abstract class Channel : Identifiable<long>
     public bool? IsAdultOnly { get; set; }
 
     [HasOne]
-    public DataStream VideoStream { get; set; } = null!;
+    public required DataStream VideoStream { get; set; }
 
     [HasOne]
     public DataStream? UltraHighDefinitionVideoStream { get; set; }