Generate "Sign in with Apple" client_secret using .NET Core (C#)

Program.cs

using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Security.Cryptography;

using Microsoft.IdentityModel.Tokens;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            const string aud = "https://appleid.apple.com";

            const string kid = "0000000000"; // Key ID
            const string iss = "0000000000"; // Team ID
            const string sub = "ServiceId"; // Client ID (Service ID)
            const string privateKey = ""; // Private Key (Base64 Encode)

            var cngKey = CngKey.Import(Convert.FromBase64String(privateKey), CngKeyBlobFormat.Pkcs8PrivateBlob);

            var securityKey = new ECDsaSecurityKey(new ECDsaCng(cngKey))
            {
                KeyId = kid
            };

            var descriptor = new SecurityTokenDescriptor
            {
                Issuer = iss,
                Audience = aud,
                Subject = new ClaimsIdentity(new[] { new Claim("sub", sub) }),
                NotBefore = DateTime.UtcNow,
                Expires = DateTime.UtcNow.AddDays(180),
                SigningCredentials = new SigningCredentials(securityKey, SecurityAlgorithms.EcdsaSha256)
            };

            var handler = new JwtSecurityTokenHandler();

            var token = handler.CreateJwtSecurityToken(descriptor);

            Console.WriteLine(handler.WriteToken(token));
        }
    }
}

This solution only for windows platform because of the "Windows CNG". I'm looking for cross platform way.