This game IS steam deck compatible !

[Cardioman]

I bought the game hoping to make it work on the steam deck, it was the only reason I bought the game, actually.
Launching it, it will give you a few error (d3d9 missing etc)

Just go in properties, compatibility, and choose Proton Experimental.
Launch the game, and use the settings window on the launcher, to put the deck's format, fullscreen, and launch the game and voilà !

The game works even better on the deck than my PC (which has the specs that can run a Red Dead Redemption 2 at 60fps) but for some reason I have huge FPS drops in the menu on the PC.

So enjoy it on the steam deck ! :)