Hi @stevensrf,
Welcome to the Auth0 Community!
You can create a .Net8 WebApi in Auth0 by following the quickstart guide for ASP.NET Core Web API Application which provides step by step instructions on how to configure your API, as well as code samples. Particularly when it comes to .Net8 you can check out this blog post which covers the latest additions on the matter.
Afterwards since you mentioned that “No user login is needed” you will have Register a Machine-to-Machine Application and use the Client Credentials Flow.
You can also follow this documentation - Self-Service Machine-to-Machine which offers a complete guideline as well.
I hope this helps!
Best regards,
Remus