I've been having a lot of problems on debian with nvidia since I upgraded to Bookworm. I even tried a few fresh installs but I think there is a bug that has something to do with screen tearing and the force composition pipeline settings.
I haven't found or fixed it in the last 6 months and my games are running very, poorly, something like you have described.
I'm kind of thinking it may be due to the nvidia transition to wayland. At the moment though I have to spend the next several months on Windows to study but when I return to debian I'm hoping wayland will be re-enabled with nvidia and I can get my games running again.
Good luck and I'll be keeping a close eye on this thread for updates.