When a Steam game is launched from the flatpak version of Steam is the game itself running within the boundaries of the flatpak’s permissions or does it launch the same as native steam? If it’s the latter then I’d say yeah, the podman setup here seems like a great way to isolate games from the rest of your system!
It says page not found when I click the github link, did you delete or change the repo name? Also, what container environment is Steam installed in, is it a CachyOS container or something else?
The project Distrobox could be of interest with this setup as it works with podman! I have used it before to try running containerized Steam and it worked great! However, in their security implications section they do state they prioritize integration with the host system over security, so this might be worse isolation than your setup, although I can’t imagine the gap is too big as getting decent gaming performance requires a good bit of host resource access.
