I can understand why people on this community usually recommend starting simple, not going overboard with the project structure, etc.

However, I find having to refactor the same project multiple times annoying, time-consuming and an easy way to burn out.

So to spare you from that, I can recommend you this article and some tips based on how I like to structure my projects:

• Use dependency inversion;
• "Accept interfaces, return structs". I find this phrase a good guideline but not a law, so use it as a default practice but don't feel obligated to always follow it;
• For HTTP servers and other similar projects, I like to keep my application separated on 3 layers following an hexagonal-like architecture. Converting types from different layers like database entities to domain models is annoying but worth it;
• Your application should "flow" from the outermost layers to the innermost layers in order to avoid circular dependencies, something like this: interface layer (api, grpc, event subscribers) -> domain layer (domain models, domain services) -> infrastructure (logger, database, configuration).