Just keep making things and research whatever you run into that you don't already know (tip: pick projects where you're going to have to research more things if you want to learn more). I don't think you're actually hindered by not being a professional SWE - I've learned more just from hacking around with personal projects than I ever have from writing code for my employers. There's definitely going to be some professional tooling and conventions that you'll miss out on, but those are only important for programming in professional settings, not for making things in general.

Contributing to open source projects is a good way to get exposure to new patterns too.