Bluesky is very easy to get into, although it's basically just "Twitter without as many Nazis" right now - its federation capabilities are barely used. Its starter-packs and algorithmic feeds are very good at quickly onboarding you.

Mastodon/Fediverse, on the other hand, is truly grassroots and federated instead of being a VC-funded cathedral, but it's just not nearly as successful and the usability barriers are higher.