I just got this laptop (Asus TUF A15 2021) today and it surprised me that everything works just fine out of the box on Vanilla Arch, except NVIDIA gpu I had to install it manually on battery power that's why I enable powersaving mode. As for games performance it's basically the same as windows no more no less.
I had recently same issue, but with a different game. Out of nowhere the performance was bad. And it took me even a day to resolve this. My PC does not need power profiles actually, its not a laptop at all. Not sure why or how the profile changed, but it got me from say 100 fps to stutter-fest 17 or something like that. I think that there was a key combination in KDE I hit by accident maybe.