Your better off with a more bleeding edge distro than Debian for gaming performance. You will be able to play games on Debian, but your going to miss out on performance from a more up to date kernel, graphic drivers, and overall software suite. Debian holds back packages for months or even years. I.E. the Nvidia driver they have is 535, released last summer, where the current beta driver is 555/560. They'll backpatch some stuff in but it'll be lackluster for trying to get the most out of your hardware.