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.