For openSUSE Leap 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.3/openSUSE_Leap_15.4/LibreOffice:7.3.repo
zypper refresh
zypper install libreoffice-writer
For openSUSE Leap 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.3/openSUSE_Leap_15.3/LibreOffice:7.3.repo
zypper refresh
zypper install libreoffice-writer
For SLE 15 SP4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.3/SLE_15_SP4/LibreOffice:7.3.repo
zypper refresh
zypper install libreoffice-writer
For SLE 15 SP3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/LibreOffice:7.3/SLE_15_SP3/LibreOffice:7.3.repo
zypper refresh
zypper install libreoffice-writer