I ran Bazzite on a mini form factor pc for about 12 months. It was just connected to the TV and used to play games.
I turned it on, I used my controller to start a game, that was it. I’m not sure what actions would be doing to break it.
I haven’t used it in about 6 months since I got a steam deck, but I just plugged it in and tried it again. Still starts up fine, played dead cells for a few minutes.
But if you’re looking for immutable distro for gaming then Bazzite is the gold standard.
Other immutable distros like Kinoite, Aurora, Aeon are targeted to desktop use, but in my experience they play games just fine too, no reason they wouldn’t (Aeon used to have a weird security policy that caused problems with Wine, but I think they changed that)
Maybe if you use Proton VPN on KDE it could need to pull in some Gnome packages. Which isn’t a problem. I use Proton VPN on KDE but I just install it from flathub to keep it simple, so I couldn’t say for sure.