Comment # 5 on bug 1230957 from Cor Blom

Musescore in Tumbleweed is still a Qt 5 app and wayland doesn't work well. It
is solved in 4.4, which is in the devel project, but not ready for production
use and Tumbleweed. Upstream is not really considering distributions and focus
on making everything work for one specific Qt version. It now has moved to Qt
6.

As a work-around, force XWayland by adding the following environment variable:

QT_QPA_PLATFORM=xcb

See also:

https://github.com/musescore/MuseScore/issues/20550

and the flatpak/hub issue:

https://github.com/flathub/org.musescore.MuseScore/issues/111

Work is under way to bring 4.4 to Tumbleweed, but it can take some time.