Willing to burn few bucks here and there for the projects.

Really need to get hands dirty here. I remember taking RL course from coursera during 2020 covid. I didn't have the chance to apply it in the problems I worked post covid.

But I really want to start doing RL again. Interested in world models and simulation for RL.

If you're good on theory (meaning able to read theory), but interested in non-LLM stuff, pufferlib and it's programmer also seem quite accessible (if you haven't come across it already).