Comment 2 for bug 1735979

Yes, this is actually the expected behavior. If netplan is configured to use the systemd-networkd backend for a given network interface (i.e. as set up by a default server installation) the "graphical UI" (NetworkManager) will ignore that interface; otherwise there would be conflicts

As you mentioned this can be changed by adopting the netplan configuration in /etc/netplan/*.yaml, defining the NetworkManager renderer, after which the interface will be handled by NM and can be controlled through the "graphical UI" and other NetworkManager tools, like "nmcli".

I don't think the user's configuration should be overwritten by installing a meta-package like "ubuntu-desktop".