How about creating your own LAN within the untrusted network?
Something like an inexpensive OpenWRT router would do fine. Connect all your devices and the server to the router. They are now on a trusted network. Set up Wireguard on the OpenWRT router to connect to Proton so that your outbound traffic from all your devices is secured.
I thought so too, but the article really delivered. I didn't know I was living in The Butthole Era. I suspected it, but I didn't know it.