Para openSUSE Tumbleweed corra o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:dliw/openSUSE_Tumbleweed/home:dliw.repo
zypper refresh
zypper install musescore3
Para 15.6 corra o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:dliw/15.6/home:dliw.repo
zypper refresh
zypper install musescore3
Para 15.5 corra o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:dliw/15.5/home:dliw.repo
zypper refresh
zypper install musescore3