How to output a formatted string from a json model class in C#

I want something like the following

using System;
using System.Text;
using System.Text.Json;
                    
public class Program
{
   public static void Main()
   {
      var myArgs = new ArgClass();
        
      // myArgs is populated via System.Text.Json deserialization
        
      Console.WriteLine(myArgs.ToArguments());
   }
}

public interface IArguments{}

public class ArgClass : IArguments
{
   [JsonPropertyName("propertyA")]
   public string PropA {get; set;}
    
   [JsonPropertyName("propertyA")]
   public int PropB {get; set;}
}

public static class IArgumentsExt
{
   public static string ToArguments(this IArguments ArgObj)
   {
      var argString = new StringBuilder();

      //Code to build argument string

      return argString.ToString();
    } 
}

So that the Console.Writeline() would output the following string

-argument propertyA="some text" -argument propertyB=123

I feel like this is something that has to be done with reflection, but I know nothing about reflection. I have tried really hard to avoid situations that require it because everything I read (or watch) says its slow.

The reason I want to do it like this is because the json string that I am deserializing has more properties that I am interested in at to moment, but I might want to use more of them in the future; like if I add more features to my app later. As it stands I can add PropC to ArgClass to pick up another json property. In which case I would want the new output of ToArguments() to be

-argument propertyA="text a" -argument propertyB=123 -argument propertyC="text c"

without having to modify ToArguments().

Or maybe make another class

public class OtherArgClass : IArguments
{
   [JsonPropertyName("propertyD")]
   public string PropD {get; set;}
    
   [JsonPropertyName("propertyE")]
   public int PropE {get; set;}
}

and have an output of myOtherArgs.ToArguments()

-argument propertyD="some other text" -argument propertyE=45.678

again, without modifying ToArguments()

I am using .Net 7 Preview and System.Text.Json (not Newtonsoft/Json.net)