Using Proton-EM in steam and heroic, I have been able to get native HDR (outside gamescope) working with DISPLAY=0 DXVK_HDR=1. Other wine/proton versions may work too as long as they support wayland. RDR2 crashes GNOME, Shadow Warrior 2 only allowed HDR with an NVIDIA GPU, but most of my other catalogue works :)
Using Proton-EM in steam and heroic, I have been able to get native HDR (outside gamescope) working with DISPLAY=0 DXVK_HDR=1. Other wine/proton versions may work too as long as they support wayland. RDR2 crashes GNOME, Shadow Warrior 2 only allowed HDR with an NVIDIA GPU, but most of my other catalogue works :)