Here is a handy class that you can use in Blazor to determine if you are executing client-side or server-side. Its included in Blazor-State
I am not fan of the "premature optimization" phrase. The phrase is subjective, and begs the question; "what is premature?
Improve the working relationships between the people that write software and the people that want the software.
When using MediatR and a single controller per endpoint the controller is beyond thin; it is micro with a base controller that looks like.
Create better error messages in dotnet core with FluentValidation.
A dotnet core Testing Convention for Fixie that supports Dependency Injection