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 :)

Seconding Bandcamp & Qobuz, or ripping CDs. I use fre:ac to get accurate FLACs.

Its Qobuz 😅

A good Foobar alternative is Deadbeef music player, another one with modular design, replaygain, and lots more. Built on GTK

Sober (flatpak) should work for Roblox :) it uses the Android version with some fixes, signing in was a little jank when I tried it but after that flawless!

Did you manually partition? It sounds like when you installed Nobara the /boot/efi partition got formatted, a similar thing happened to me recently (just wasnt paying attention), I used a Windows install USB to get a command prompt and restore the EFI entry.