I don't have data, but I think going with ActivityPub also helps Meta to hurt BlueSky and their AtProto. By adopting ActivityPub, Meta is making it a Market Standard. Their userbase is huge, and other apps will need to use it to integrate with them. Why would someone adopt AtProto?

Nope.

I'm having fun here, will likely stay for long.

My main issue right now is that, I use Reddit mostly for participating in tech communities and they don't seem to exist here... yet.

I hope that changes in the soon future.