Just saw this: https://www.reddit.com/r/Ubuntu/comments/1g2bdwl/ubuntu_2410_full_of_bugs/
So I posted:
1. MuseScore 4 CAN’T PLAY AUDIO.
2. I think login took longer?
3. Disable Weyland (at login) switch back to X11 display
4. I rolled back using “timeshift” twice back to 24.04. Both times, MuseScore starts working again for playback of MIDI audio. Inbetween I back-upgraded to 24.10 and again it would not play. So I got back to 24.04.