Getting the JsonPropertyAttribute of a Property

I found a post with a great answer for a problem I have, but I can't seem to find a small detail I'm looking for.

public class myModel
{
   [JsonProperty(PropertyName = "id")]
   public long ID { get; set; }
   [JsonProperty(PropertyName = "some_string")]
   public string SomeString {get; set;} 
}

I need a method which returns the JsonProperty PropertyName of a specific property. Maybe something where I can pass the Type and the Property I need, and the method returns the value if found.

Here's the method I found which has me in the right direction (I believe) taken from here

using System.Linq;
using System.Reflection;
using Newtonsoft.Json;
...

public static string GetFields(Type modelType)
{
    return string.Join(",",
        modelType.GetProperties()
                 .Select(p => p.GetCustomAttribute<JsonPropertyAttribute>()
                 .Where(jp => jp != null)
                 .Select(jp => jp.PropertyName));
}

The goal is to call a function like this (any modification is fine)

string field = GetField(myModel, myModel.ID);

Thanks!