For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:EGDFree:vacuum-im:git:qt5/openSUSE_Tumbleweed/home:EGDFree:vacuum-im:git:qt5.repo
zypper refresh
zypper install vacuum-im
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:EGDFree:vacuum-im:git:qt5/15.5/home:EGDFree:vacuum-im:git:qt5.repo
zypper refresh
zypper install vacuum-im
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:EGDFree:vacuum-im:git:qt5/15.4/home:EGDFree:vacuum-im:git:qt5.repo
zypper refresh
zypper install vacuum-im