As per the linked FAQ,
What platforms will Sid Meier’s Civilization VII be available on?
Sid Meier’s Civilization VII will be available on PS5, PS4, Xbox Series X|S, Xbox One, Nintendo Switch, and PC via Steam (which also supports Mac and Linux) and the Epic Games Store.
The Steam store (preorder) listing shows all three platform icons so I’m guessing they’re not just talking about making it work with Proton.
No mention yet of Aspyr (who ported Civ 5 & 6) as far as I can see.
I’ve had this experience with other games too. Some “native” Linux versions won’t even launch so you have to use Wine or Proton.
When this is the case it’s nearly always a missing library the game (or steam?) didn’t declare as required, ime. If you start the game from the terminal you can usually figure out which library it is and get it up and running, tho it’s usually easier to just use proton