You can use nmcli to configure network interfaces controlled by NetworkManager. But, honestly, I don’t see any advantage to learning the cryptic CLI instead of using the cryptic config file stuff I’ve already learned. And yet … I need my server to have /etc/resolv.conf populated when it reboots. So I figured out how to launch the KDE system settings (assuming you’ve got the X display redirected to your host) — systemsettings5

Mine takes a few minutes to render, during which time the window is black and a handful of errors are written out to the console. But it got there eventually, and I was able to edit the network interface.