What are some sublemmies you recommend?

I think the best approach is playing the long game with the 'All' feed because lemmy is so small, which is the approach that I've taken.

Basically you'd be blocking all the communities that don't interest you, foreign language servers you can't understand, and a couple prolific bot accounts reposting everything from reddit. That approach will take a good long while to weed out everything you don't want to see and be left with things you like and weird and varied discussions that are fun to engage in. This works in your favor in the long run because new communities crop up on your feed now and then that you'd never come across otherwise.

That being said, I recommend any of the asklemmy or ask (group) communities for good interaction and reading material, and the million cat communities that make your feed whether you want it or not