https://protonvpn.com/support/official-linux-vpn-ubuntu
Installing
ProtonVPN in Linux is a GUI app. See Setting up an x11 VNC on an Ubuntu Machine to set up VNC if you’re on a headless server.
wget https://repo.protonvpn.com/debian/dists/stable/main/binary-all/protonvpn-stable-release_1.0.8_all.deb
sudo dpkg -i ./protonvpn-stable-release_1.0.8_all.deb && sudo apt update
sudo apt install -y proton-vpn-gnome-desktopRemoving
sudo apt autoremove proton-vpn-gnome-desktop && sudo apt purge protonvpn-stable-release