Hey all,
This small update adds more configurable options on Steam Deck and fixes L2/4/5 R2/4/5 not being assignable from game.
There was also a change to recommended controller layout, I am not sure if Steam updates it automatically. If the update does not enable triggers for you then please try go the Steam Deck setting for controller layouts, and reapply the official layout (just press 'X' when viewing it).
Small update fixing Steam toggles and additional buttons (L2/4/5 R2/4/5)
Source: Steam Community (opens in a new tab)