Understood. If you're into Marxism-Leninism, I know Lemmygrad.ml has some reading groups (both a weekly theory thread and a weekly general literature thread), and Hexbear.net has study groups on anti-Zionism, anti-imperialism, and standard self-improvement threads. Blahaj.zone is defederated from both, so you'd need to make another account to access them.

I know there are many communities for computer science around here, though fewer for language learning, philosophy, and fashion.