I'm on Lemmy essentially 99% of the time. When I'm on Reddit it's because of niche hobbies that have more presence there. It's very rare. (Or search index results.)
I never use Mastodon. I was only on Twitter for very niche and interactive hobbies that do not have enough people to engage with on Mastodon. I mostly use BlueSky now but still use Twitter on occasion. It's like 50/50 at the moment, but that's a lot considering my BlueSky account is only like two weeks old.
Lemmy has enough content to keep me entertained for general browsing and most of my hobbies.