When using .AddOpenIdConnect() within ConfigureServices, is it possible to change the ClientId and ClientSecret based on the host from the request?

I know the Startup itself doesn't have access to the HttpContext, but I was wondering if using a middleware would solve this where it would have access to the context.

I've tried following the below link, however my values are always null after it runs through the CustomAuthHandler ASP.NET Core 2.0 authentication middleware