First, thanks everyone who responded. I finally have a little time to start working through it, which I'm undertaking now, so I'll probably have a heap of questions.
said Michele Calgaro via tde-users:
| not sure about the specific of how protonvpn interacts with the systray, | but you can use tdedocker to dock any application to the systray in case | nothing else work. Run protonvpn window, then run tdedocker and click | the proton vpn window to dock it.
Thanks. This works and I'll use it as a fallback if I can't restore the original bahavior. The original Proton version had a useful status indicator. But in the swing of things that's not essential.
While I'm here, a warning: Before I set up Starlink and was stuck with the Arris router that the telephone company provided, the signal to the living room was not as strong as I liked, so I got an EDUP USB wifi antenna from Amazon. Oddly, it kept turning off the VPN (which, the way I have it set up also turns off the wifi itself into the machine). With the much stronger signal from the Starlink router, I was able to remove the Amazon antenna and suddenlt no more disconnects. Poking around, I found that it wasn't just an antenna but a whole Mediatek wifi card built in to the thing and using that in lieu of the Broadcom in the Raspberry Pi. Poking around further, it seems there are security concerns about the aii-on antenna/wifi circuitry. So, avoid! (Ultimately didn't matter here because everything was encrypted before it got transmitted, but was inconvenient.)