I know it’s a bit of an edge case, but afaik this is the preferred way to use ProtonVPN on a Chromebook. I’m using an Acer Spin 714 and the current Play Store beta version of the Proton VPN app (4.3.49.0).
If I use quick connect and leave everything to default the initial connection is fine, but after the 'book sleeps and then I wake it, it goes into a reconnecting loop. Closing the app and reopening after this happens does not fix the connection. If I switch the protocol to OpenVPN UDP or TCP, I am able to connect. So far, at least OpenVPN UDP is able to reconnect after wake from sleep.
I can supply logs and run adb commands “into” the Chromebook Android layer if necessary.