Menus and overlays work fine but all 3D objects are shown only as greyish/brownish silhouettes regardless of in-game graphics settings, rendering the game unplayable. The issue can already be seen on the globe/characters in the main menu. When starting the campaign, all objects are still just silhouettes with some textures leaking between objects like clouds.

Tested with Nvidia drivers 550.120 and 550.127.05, Proton 9.0-3 and Proton Experimental (using compatibility options via Steam).