I would like to support gaming on Linux, but do not want a game sniffing /proc as I suspect some do, or will shortly do. The equivalent practice under Windows is common as an anti-cheat measure.

If you want to game, I recommend dedicating a separate Windows machine to the task.

I run the flatpak version of Steam, and repackage GoG games for flatpak too.

As a result, games are getting nicely filtered /proc.

Do you have a tutorial to repackage non-DRMed games for flatpak, for personal usage? Could be very useful!

No tutorial, just organically grown (thus ugly) scripts for games, that I own.

The gist is to prepare the directory structure, icon, .desktop file, flatpak metadata, appstream info, add dependencies not provided by flatpak runtime (for games, libGLU for example), put everything into ostree repo (flatpak build-export ...), and then either install from that, or export the content into .flatpak file (flatpak build-bundle ...).

The last step can take a while, .flatpak files are lzma compressed and the compression during export uses only one cpu core. For 20GB game, that isn't exactly quick, to be diplomatic.

I had a Windows partition for gaming but since Wine got better, more Linux games are available and setting up a proper dual boot with Windows become a pain I deleted windows.

As a fallback if some new game appears and I really want to play it I can get it on my kids console.