Use keytable 'us' instead of 'us.map.gz'.
Switch from obsolete package nfsidmap to libnfsidmap1 in SLE 15 SP6.
Use systemd-sysvcompat in SLE 15 SP6 instead of systemd-sysvinit (package rename).
Fall back to locally assigned link-local IP address in case DHCP fails. This helps work around the issue that in EC2, instances in IPv6-only subnet do not have access to IMDS IPv6 endpoints by default.