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 reboot
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.