The Empirical Manifesto

https://documentation.suse.com/suma/4.2/en/suse-manager/client-configuration/client-upgrades-major.html

* for worky-work add proxy=[proxy] for Kernel Options (may not need)

You need at least SLES 12 SP5 before you can proceed to SLES 15 SP3/4
Upgrading from SLES 12 SP5 is only supported via an offline upgrade.

# zypper packages --orphaned
# zypper packages remove [module module module] (for Unknown URL in Add-Ons)

Systems --> Autoinstallation --> [upload autoyast.xml] --> Next -->

Add to Distribution KERNEL OPTIONS:
autoupgrade=1
useonlinerepo
insecure=1

Add to Profile VARIABLES Text Box:
IPADDR=192.168.1.69
GATEWAY=192.168.1.1