Proton VPN CLI - UFW Kill Switch on Raspberry Pi, Libre Renegade and PC Ubuntu 18

How to install and use Proton VPN Command Line Interface with UFW as a Kill Switch on a Raspberry Pi 4B 8GB, and a Libre Renegade both running Ubuntu 22 Jammy Jelly Fish as well as a PC running Ubuntu 18.04 Bionic Beaver.