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.
Undervolting is great on gaming laptops. Usually nets you a performance boost simply by reducing thermal throttling.
Even just a few mV has made a difference for me.