That's why I have come to accept that it's more of a "me" problem, because I struggle against it late game more than early game.You're right that Zama can deal with a lot by itself, but there's a lot of cores that handle it together and minimize how much it can get away with. IDBP Zama has 3 required moves in Body Press, ID, and Crunch, so it only has one move slot free. Lando+Glowking/Ghold weakens Crunch which is the only move Zama can hit them with. Ghost/Glowking + Moltres can scout Stone Edge and bait Zama into crunching and getting burned. Fairy/Burn + strong Ground type can force Zama to tera fire and be handled by ground types, though ID makes that less reliable. Moon/Dragonite / Waterpon can force it to come out early and take good chip that makes it harder for it to set up later.
Zama wants a lot of coverage but commonly used cores can handle it well. It also is usually forced to come in earlier than it would like because of its defensive utility and then loses some of its ease of setup.
I don't know why. I tend to struggle with fast hard hitting mons than the slow ones. Outside Ursaluna-Blood Moon and probably Scor, I have never had much trouble against slower mons.