I mostly use Tumblr, so any drawing of my OCs may get some engagement, but any random post I make relating to any fandom will get the most traction.
Case in point: My post about a few sketches of my OCs, Tsukasa, in a witch costume has gotten 4 likes, but my post promoting George Harrison's Living in the Material World 2024 reissue has gotten 17 likes and 4 reblogs. So I plan on doing fanart in order to get some engagement.
I also use Cara, but that's a wholly different thing, and I've gotten zero engagement there so far.
I don't use Facebook, Instagram, or Twitter (not calling it "X") because those platforms have their own problems, especially with the latter.