using System;

using System.Text.Json;

public class Program

{

    public static void Main()

    {

        var wrongJson = "{ Name: \"бла-бла\", Value: \"666\" }";

        var rightJson = "{ \"Name\": \"бла-бла\", \"Value\": 666 }";

        Console.WriteLine(JsonSerializer.Deserialize<DTO>(rightJson));

        Console.WriteLine(JsonSerializer.Deserialize<DTO>(wrongJson));

    }

}

​

public class DTO

{

    public string Name { get; set; }

    public int Value { get; set; }

    public override string ToString() => $"Name={Name}, Value={Value}";

}