Fact. I game on Debian (mostly through Steam flatpak) and it works great. I tried the so-called “gaming” distros and eeked out 0-5% fps gains while also experiencing paper cuts or bugs in other areas of my daily driving that weren’t present on Debian. I’m not into e-sports so so long as I’m not hitting a 30 fps floor I’m fine. The time I save not having to navigate paper cuts I get to put toward fun things, like actually playing games.
(Edit: typos)
I don’t have a recommendation other than don’t recommend something to your friend for which you’re not willing to provide tech support.