Ubuntu Server + Xubuntu-core

Simple How-To for adding a graphical display to a base Ubuntu Server 20.04 system.

sudo apt update && apt upgrade -y
sudo apt install lightdm tasksel
sudo tasksel install xubuntu-core

Should you install multiple desktop environments, to specify the default session, use the following command.

sudo update-alternatives --config x-session-manager 

When the system has rebooted you will be able to log into the xubuntu desktop. The -core indicates just the core desktop environment rather than the numerous recommended / associated apps.

Other desktops are just as easy, want mate, then its ubuntu-mate-core. Lubuntu is lubuntu-core. You get the idea.