I recently signed up with ProtonVPN.

Here’s how I connect in Arch Linux.

sudo pacman -S openvpn

sudo wget -O protonvpn-cli.sh https://raw.githubusercontent.com/ProtonVPN/protonvpn-cli/master/protonvpn-cli.sh

sudo chmod +x protonvpn-cli.sh
sudo ./protonvpn-cli.sh --install
sudo protonvpn-cli -init
sudo protonvpn-cli -connect
sudo protonvpn-cli -disconnect