For standard run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:owinebar:Staging:gcc12-bootstrap/standard/home:owinebar:Staging:gcc12-bootstrap.repo
zypper refresh
zypper install cross-arm-none-gcc12-bootstrap
For custom-gcc11 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:owinebar:Staging:gcc12-bootstrap/custom-gcc11/home:owinebar:Staging:gcc12-bootstrap.repo
zypper refresh
zypper install cross-arm-none-gcc12-bootstrap