This has been driving me up the wall as there should be no reason why AddDbContext in startup.cs isn't working. Anyone have any thoughts?

Project specs: .net 5, EF Core 5, MVC

PsContext.cs

public PsContext()
{
}

public PsContext(DbContextOptions<PsContext> options)
    : base(options)
{
}

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    if (!optionsBuilder.IsConfigured)
    {
        optionsBuilder.UseSqlServer("name=PSDB");
    }
}

Startup.cs

services.AddDbContext<PsContext>(options =>
{
    options.UseSqlServer(Configuration.GetConnectionString("PSDB"));
});

Appsettings.json

"ConnectionStrings": {
    "PSDB": "Server=xxxxxx;Database=xxxxxxx;User ID=xxxxxxx;Password=xxxxxx;MultipleActiveResultSets=true"
},

I scaffolded my DB Entity without issue by using the following command in Package Manager Console

Scaffold-DbContext -Connection name=PSDB Microsoft.EntityFrameworkCore.SqlServer -OutputDir Entities -f

However when running the application, I encounter this error

System.InvalidOperationException: 'A named connection string was used, but the name 'PSDB' was not found in the application's configuration. Note that named connection strings are only supported when using 'IConfiguration' and a service provider, such as in a typical ASP.NET Core application. See https://go.microsoft.com/fwlink/?linkid=850912 for more information.'

As requested, here is the program.cs as well

public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((hostingContext, config) =>
                {
                    config.Sources.Clear();
                    var env = hostingContext.HostingEnvironment;
                    config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                          .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)
                          .AddEnvironmentVariables();
                })
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }