Depends on which i come across first.
I usually go to mangaread or something, and i'll read things that get my attention. I've read multiple mangas before they got an anime adaptation (and in the last few years, most of them are really faithful).
But i've also watched anime that i've never read the manga to, a lot of the isekai and dating sim related ones, 8th timeloop, love is difficult for mob background characters, etc. I also haven't read any Demon Slayer and yet there's now 5 seasons out (and only seen season 1, just before the train).
Though one that is currently coming out that i read in manga (when it was translated) was I'm a S class behemoth but my elf master thinks I'm a cat. Just too bad there's only so many chapters. Same with Skeleton who couldn't protect the dungeon, World with Cut & Paste, Arcane Sniper, Isekai harem in a dungeon, auto hunting with my clones, and a bunch of other manga.
And jumping among them gets exhausting... Especially when you're waiting for chapters to come out every few days...
Some manga.... goes in weird directions. and you just drop it. Or there's 400+ chapters and about 150 chapters it feels like it's kinda pointless to keep reading (solo leveling comes to mind) but would probably be better as an anime if they get to going past season 1.