llvmpipe is the only video device

LMDE 6, 5900x, GTX 1060 6gb, running through Steam with GE Proton9-11 (tried a bunch of other versions with similar results)

I'm not really sure what llvmpipe is all about but I haven't seen this problem in any other game before. As far as I can tell everything else is fine.

So the game just isn't seeing my GPU at all? Maybe 535.183.01 nvidia driver is no good?

I could really use a hint which way to approach this problem if anybody has seen such a thing before.