Team-based hackathons are always fun. In-person is better, but remote is good too. Lots of intense collaboration.

Multi-day conferences or events with discussion panels, socials, or Q&As are all places to hang with, drink/eat with, and interact with people from all around an area who all share a common interest.

Find the Slacks / Discords for the groups you’re interested in. Crash out of those weirdos and find new ones. This one is tough, but not impossible.

This one is weird, but you could start a tutoring group. There are probably other students and studiers, and reinforcement learning and pair learning might be really beneficial, allow you to provide a service, and meet new people.

Just a few that came to mind quickly