Hey!
I use Heroic Games Launcher to enjoy my GOG library on Steam Deck.
I've been trying without luck to play BG:EE there. It just doesn't launch.
I've tried both, Linux and Windows installs.

Any idea about what can I be missing or any potential workaround??

./play.it can be used to install BG:EE on several Linux distributions, including SteamOS.

I have not tried it that way myself, as I don’t own a Steam Deck and see no purpose on installing SteamOS on a regular all-purpose computer.

try a MacOS install lol

I may have just gotten it to work. I've been trying to do this too, and what i did is I installed it via the Heroic Launcher. Windows version. I then launched it from the Heroic Launcher in desktop mode, and it looked like it installed some more files related to GoG and it launched. I'm about to test to see if it will now launch in game mode.

EDIT:

I just want to add that I can't get it to launch from Steam in gaming mode, only when I launch it through Heroiic directly in desktop mode. Not sure why that is, but it is.

EDIT2:

Ok, got it to launch in gaming mode. In the compatibility settings, I had to turn off "Force the use of a specific Steam Play compatibility tool" where i had set to 7.0.6. Apparenly that lets it launch now, so all i have to do is set up controller now.