Individual game subs. Even a niche game usually had just enough of an active community that I could talk about it get help with pretty much anything.
The generic "Gaming" and "PC gaming" and even "BoardGames" crowd is here; but they're mostly good for general news, not discussion of specific games. If I want discussion about lore in Baldi's Basics, for example, I ain't getting it in the general communities.
I feel you, I've been super active in a niche community of a game ( /r/ADCmains from League), and even though it was a salty shitshow, I enjoyed it there.
I got some of that fixed by joining a discord, but it's not the same :/