I've got audio working on MuseScore4 + Void Linux! A little summary of what I did (for myself and anyone else on #linux needing #MuseScore 4)
I first switched to #pipewire. For me, this involved uninstalling #pulseaudio and jack, then installing the packages `pipewire alsa-pipewire`. This differs on other distros. I needed to verify that pipewire was starting up properly. Since I didn't have a login manager, I had to set the XDG_RUNTIME_DIR variable manually and also create that directory everytime I booted. Using `tmp` instead of `run` worked better for me.
Then I followed these steps: https://docs.voidlinux.org/config/media/pipewire.html#alsa-integration to get #alsa integration going. Restart, then that's it!
MuseScore now has audio