I realise this is a rather old topic, but +1 for "official" linux support – the gog version works fine under proton (I <3 DRM-free stuff and buy everything on GOG, although I admit that proton is fantastic).
It would be good to have either some official support or a statement along the lines of "We don't officially support you, but the following definitely works on our testing: " – which is what EVE online does, for example.
Honestly, with the Steam Deck it's probably a good idea to make it relatively cross platform anyway!
