Follow
If you've installed #Steam from a #Flatpak on #Linux, Windows games will not launch with #Proton. The Play button goes straight back to saying "Play", with no errors or other windows appearing.
Install Steam normally and you're good to go.
I deleted my ~/.var/com.valvesoftware.Steam directory (where the Flatpak version keeps everything) and re-downloaded my games, YMMV.
@Taffer Yes, proton can't work ootb in Flatpak anymore. It's being worked on, but in the meantime:
https://github.com/flathub/com.valvesoftware.Steam/issues/642#issuecomment-716580163