This is how I retrieve the user from my request without tears

ExtractUserExtension.cs

using Microsoft.AspNetCore.Mvc;
using System.Linq;
using System.Security.Claims;
using System.Threading.Tasks;

namespace TwoDrive.Api
{
    public static class ExtractUserExtension
    {
        protected static string GetLoggedUserId(this ControllerBase ctrl)
        {
            return ctrl.User.Claims
                .Where(c => c.Type == ClaimTypes.NameIdentifier)
                .Select(c => c.Value)
                .SingleOrDefault();
        }
    }
}