On Ubuntu Server 20.04 I've found that I'm having some trouble getting plain old
startx to work for users after installing MATE desktop. GDM can start up fine as well as LightDM, but when I kill them off and manually respawn them via
systemctl I'm finding that it doesn't work as cleanly as I'd like. My goal is to simply use the shell to login to an account and then spawn MATE via a simple
startx (or some such shell script) after getting into the system and then if and only if I decide that I want to run X.
How's this accomplished in 20.04?