Google JWT (without secret validation)

JWT_Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using System.IdentityModel.Tokens.Jwt;
using Microsoft.IdentityModel.Tokens;
using System.Security.Claims;

namespace API
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            services.AddAuthentication();
            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddJwtBearer(jwtOptions =>
                {
                    IConfigurationSection googleAuthNSection = Configuration.GetSection("Authentication:Google");
                    // jwtOptions.Audience = "{the OAuth 2.0 client ID credential from google api developer console}";
                    System.Console.WriteLine(googleAuthNSection["ClientId"]);
                    jwtOptions.Audience = googleAuthNSection["ClientId"];
                    jwtOptions.Authority = "https://accounts.google.com";
                    jwtOptions.TokenValidationParameters = new TokenValidationParameters();
                    jwtOptions.TokenValidationParameters.ValidIssuers = new List<string>()
                        {
                            "https://accounts.google.com",
                            "accounts.google.com"
                        };
                });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthentication();
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
                endpoints.MapRazorPages();
            });
        }
    }
}

// using     "Hellang.Authentication.JwtBearer.Google" Version="2.0.0" 
// https://github.com/khellang/Middleware
            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddJwtBearer(x =>
                {
                    IConfigurationSection googleAuthNSection = Configuration.GetSection("Authentication:Google");
                    x.UseGoogle(
                    clientId: googleAuthNSection["ClientId"]);
                });