No need get window. You need somes tools though.

From the stock app market (called discover) :

  • Transmission
  • Lutris
  • ProtonUp-QT to install ProtonGE

From GitHub:

  • Decky (and the addon SteamGridDB)

On desktop mode. I download my games as torrent from dodirepack or fitgirl 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. (Find steam game I’d on the site SteamDB)

In game mode I then setup images 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)