Are you using latest DXVK and Proton Experimental and also set DXVK_HDR=1?
Yes, although Hogwarts Legacy is a directx 12 game I think.
I also seem to have this problem with Mass Effect Legendary Edition too.
Hogwarts legacy seems to be working now, but not Mass Effect Legendary Edition.
Moving this to DXVK as Mass Effect is not a DX12 game.
Many DX11 games will probably not work right now or ever because they use vendor libraries like nvapi or amdags to enable HDR.
I've gotten HDR enabled in gamescope and my display detects the HDR signal, but hogwarts legacy still keeps its HDR firmly disabled. Does anyone else have this problem?