I worked with Support for 5 days without results. I have UbuntuMATE 22.04 not Ubuntu Gnome. At the CLI, “sudo apt install gnome-shell-extension-appindicator gir1.2-appindicator3-0.1” tells me it can’t find this extension. however the ProtonVPN app successfully installs on the launcher and works until I reboot. Then NO DNS.
Cheers.