No need get window. You need somes tools though.

On desktop mode I download my games as torrent from dodirepack with the software transmission(from stock appshop). Once I have a game I use Lutris(from stock appshop) to execute the installer. Then I add the game to steam on desktop mode. And I rename the game to their steamid to be able to search for contrôler config. I then setup imagesin game mode for the games with the addon SteamGridDB installed from Decky (and addon loader for steamdeck)

If I have trouble running game I use protonGE which I installed with ProtonUp-QT (from stock appshop)