# netplan set "ethernets.ens160.addresses=[172.17.12.91/24]"
# netplan set "ethernets.ens160.gateway4=172.17.12.1"
# netplan set "ethernets.ens160.dhcp4="
# netplan set "ethernets.ens160.nameservers.addresses=[1.1.1.1, 9.9.9.9]"
This is a collection of techical information, much of it learned the hard way. Consider it a lab book or a /info directory. I doubt much of it will be of use to anyone else.