I just downloaded Yamagi 8.10 and uncompressed it on the GOG Quake 2 directory. I overwrote the files (quake2.exe adn some DLL). After that, Yamagi client runs instead of standard Quake2, so music works, I can choose higher resolutions, better OpenGL support and general better experience.

Music works only with Yamagi, will never be fixed...

It's a bug of Windows 10 & 11

Only if it is some newest OS builds bug. Music should work up to some older versions of Win10. But since this (and many else) threads exist for many years - it is not a thing to be fixed. Something on your system end.

Just normally reinstall game. To proper game path. By admin. Start game from GOG included launcher. There is no big issues, should be playable, with music, and almost with no issues (except really ones exist from game creation and never be fixed).