Can I use C#?

The documentation details connecting with UMAPI using Python (Samples) however here is a C# sample for reference...

Generating a JSON Web Token (JWT):

 using System;
 using System.Collections.Generic;
 using Jose;
 using System.Security.Cryptography.X509Certificates;
 using System.Security.Cryptography;
 
 // the namespace would be the name of your project, mine is "aaa"
 namespace aaa     
 {
     class MainClass
     {
         public static void Main (string[] args)
         {
            DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);
             TimeSpan diff = DateTime.Now.ToUniversalTime() - origin;
             var span =  Math.Floor(diff.TotalSeconds) + 60*60*24;
                                                                                              
             var payload = new Dictionary<string, object>() 
             {
                 {"iss", “enter-yours"},
                 {"aud" , "enter-yours"},
                 {"exp", span},
                 {"sub", "enter-yours"},
                 {"https://ims-na1.adobelogin.com/s/ent_user_sdk", true} 
             };
 
             var privateKey=new X509Certificate2("my-key.p12", “xxxxxx", X509KeyStorageFlags.Exportable | X509KeyStorageFlags.MachineKeySet).PrivateKey as RSACryptoServiceProvider;
 
             string token=Jose.JWT.Encode(payload, privateKey, JwsAlgorithm.RS256);
             Console.WriteLine (token);
         }
     }
 }  

Using the JWT to retrieve an Access Token:

 using System;
 using RestSharp;
 
 namespace project2
 {
     class MainClass
     {
         public static void Main(string[] args)
         {
             var client = new RestClient("https://ims-na1.adobelogin.com/ims/exchange/jwt"); // replace with production if necessary
             var request = new RestRequest(Method.POST);
 
             request.AddHeader("cache-control", "no-cache");
             request.AddHeader("content-type", "application/x-www-form-urlencoded");
             
            request.AddParameter("client_id", "your client id");
             request.AddParameter("client_secret", "your client secret");
             request.AddParameter("jwt_token", "your jwt token");
 
             IRestResponse response = client.Execute(request);
             Console.WriteLine(response.Content);
         }
     }
 }