This is a problem that I've ran into on Crossover ever since November 2022. On any Crossover version, 21.2, 22.1...
Specifically in online (story mode is not affected), I encounter huge fps drops, pretty much halving my framerate if not more, every ~15 seconds. I could be on 50fps on my M2 MacBook Air, and then suddenly it drops down to <15fps for ~15 seconds, sometimes more, and then goes back to normal for another short period of time, before repeating itself. I play with keyboard and mouse.
This has proven to be extremely annoying, essentially making the online experience completely unplayable. As aforementioned, this has been an issue for over half a year now.
And I'm not the only one encountering this. It would be greatly appreciated if this issue were looked into and subsequently fixed, because in the state that the bug is in right now, GTA online is pretty much impossible to play with those massive drops.