The main issue I have with Lemmy however is the profound lack of discoverability for communities. This is exacerbated on smaller instances. It is human nature to want to be where many people are, and Fediverse instances are no exception there.

I’ve learned it with Stanford’s CS193p course. https://cs193p.sites.stanford.edu/

It’s the best way to learn both the platform fundamentals, as well as good programming principles. Beware though, it’s definitely for advanced students, and there’s homework.