Hmm… ProtonVPN team solved this in better way. They put the repo configuration stuff into DEB file, so it’s just a matter of double clicking it and clicking install on Debian-based and Ubuntu-based (I know Ubuntu is Debian-based) distros and then installing the ProtonVPN client through either GUI or CLI package manager, whichever you wish to use. More newbie-friendly.

Unfortunately, I also just learned they dropped support for Arch Linux :(

We’d love to support the new app for arch Linux but honestly we’re understaffed and don’t have the bandwidth to be supporting the same distros that we did before with the previous client (4 packages before vs 10 packages now). If anyone from the community is willing to make AUR packages for themselves and publish/maintain them we’re totally fine with that, as long as people keep in mind that it would be an unofficial version because we currently don’t support arch Linux with the new v4 app.

Also if anyone’s interested: https://boards.eu.greenhouse.io/proton/jobs/4140067101