For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Publishing:TeXLive/openSUSE_Tumbleweed/Publishing:TeXLive.repo
zypper refresh
zypper install texlive-scheme-full
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Publishing:TeXLive/openSUSE_Factory/Publishing:TeXLive.repo
zypper refresh
zypper install texlive-scheme-full
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Publishing:TeXLive/15.6/Publishing:TeXLive.repo
zypper refresh
zypper install texlive-scheme-full
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Publishing:TeXLive/15.5/Publishing:TeXLive.repo
zypper refresh
zypper install texlive-scheme-full