No matter how hard core cli user you are it very often that you will need a GUI to perform some tasks just because, you can’t remember the commands or you want a better visualization (Firewall ports comes to mind).
I know some prefer Cockpit but I vote for Webmin. Here is how to install in on Ubuntu 20.04
SSH to your server and get root privileges.
sudo su
Edit the repositories list
nano /etc/apt/sources.list
Scroll all the way to the end of the file and add
deb http://download.webmin.com/download/repository sarge contrib
Save and Exit
Download and install the key of the author
wget -q -O- http://www.webmin.com/jcameron-key.asc | sudo apt-key add
apt update
to update the repositories
and install webmin
apt install webmin
Now you can access the GUI interface by
https://<IP address or FQDN>:10000