For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:bjin01/openSUSE_Tumbleweed/home:bjin01.repo
zypper refresh
zypper install zabbix-agent
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:bjin01/15.6/home:bjin01.repo
zypper refresh
zypper install zabbix-agent
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:bjin01/15.5/home:bjin01.repo
zypper refresh
zypper install zabbix-agent