using System;

using System.Text.Json;

using System.Text.Json.Serialization;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        JsonSerializerOptions SerializerOptions = new() {

            PropertyNameCaseInsensitive = true,

            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,

            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,

            UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip

        };

        var str = @"{""hoge"": ""aaa"", ""fuga"": ""bar""}";

        var deserialized = System.Text.Json.JsonSerializer.Deserialize<SomeClass>(str);     

        Console.WriteLine(str);

        Console.WriteLine(deserialized);

        Console.WriteLine(deserialized.Hoge);

        Console.WriteLine(deserialized.Fuga);

        var newtonsoft = JsonConvert.DeserializeObject<SomeClass>(str);

        Console.WriteLine(newtonsoft);

        Console.WriteLine(newtonsoft.Hoge);

        Console.WriteLine(newtonsoft.Fuga);

    }

}

​

public record SomeClass(string Hoge, string Fuga);