Thanks for the response, I actually figured it out.

If I run GE-Proton9-27, Frame Gen works fine. If I use anything newer than GE-Proton9-27, I get the DLSS option, but only AMD FSR3 Frame Generation - It seems like a regression with recent Proton builds, as it also happens under Steam Proton 10.

I might try running a newer version of Proton when I get time and see if the launch option you’ve quoted resolves the issue, right now I’m just glad to have Frame Gen working again.

Did my part. If I have to run Windows along with a root kit to play a game, I’ll stick to Linux.

TBH, the game wasn’t really that great to begin with.