How to deal with a dangling kill switch virtual network interface?

I tried to uninstall ProtonVPN but unfortunately it didn’t uninstall properly and left a dangling pvpn* network interface that blackholes your entire traffic, which is a leftover from the kill switch feature.

It’s likely that ProtonVPN left a connection configuration with the NetworkManager for the kill switch feature. You can check it like so:

$ sudo nmcli con show

If one of the connection looks like pvpn-killswitch, that’s the culprit. To delete it, run:

$ sudo nmcli con del pvpn-killswitch

And your problem should hopefully be fixed.