The issue that you're going to run into with Ubuntu, or any other linux distribution, is X server. When there's no monitor connected, X server basically gives up and says "Well there's nothing for me to do around here." Any form of remote access software like Meshcentral, Teamviewer, Rustdesk, Anydesk, Zohoassist, etc will then lag like you wouldn't believe (I'm talking 20 seconds or more to see the result of an input).

We've tested this extensively because we were planning to deploy Ubuntu machines that would have a desktop, but generally not be expected to have a monitor plugged in (don't ask, long story). The only way around it that we found was using a dummy plug to keep X thinking that there's a monitor plugged in.