I have no problem installing games via their GoG installer with the Heroic Games Launcher on my main Fedora PC. However on the Steam Deck when I click “Add Game” and then fill in the name and click on “Run Installer First” the installer launches and then tells me that it could no find the other .bin files. I tried moving the directory to other places, but it seems like wine cannot find the files. I checked the directory permissions and all users have read access to those directories, yet they do not show up in the mounted filesystem in wine… (the GoG installer lets you choose another location of the files if it cannot find them)
Nice! And you remembered its called Flatseal, good! Just FYI, I don’t think installing it as native app would have solved this due to the immutability of SteamOS, I think those apps would get deleted. Installing via Flatpak gets round this issue.