Currently by default Limbo seems to installs on the Steam Deck as the native port (shows "Linux runtime" in the additional info panel), but it's unplayable : boots to a white screen with in game sounds in the background....
The issue seems to have been caused by running the game above 60 FPS. Setting my monitor refresh rate from 144Hz to 60Hz fixed both Proton and Native version! (btw, there are some other ways to do this too, like setting ...