Hi, I've been solo developing laravel projects and I've been having difficulties adopting a project where the features keep growing from time to time. The API project that I have now is a mess and I am finding a way to make it adaptive when there's a new feature again, any updated basic boilerplate for laravel API with request validations, services, interfaces, broadcasting and etc. proper usage if its a TDD boilerplate might be better.
What you're describing here is not boilerplate, it is the structure or "architecture" of your codebase. There is no one-size-fits-all rule when it comes to this, and it's hard to recommend anything without having a look at the actual code base.
You can take a look at ADR, Ports and Adapters, Vertical slices, Modules if maintainability is your concern (always take those with a huge grain of salt).
If your only concern is discoverability, then move files around until it makes sense for you. There is no right and wrong.