I think this is a sound way of doing it. Rather than trying to force people to switch and potentially alienating them from using an app like signal and moving away from their usual apps. The people who really want to continue chatting with you will come along for the ride.
Go to ipleak.net and activate the torrent check, paste the magnet link into your torrent app while on VPN and it will tell you what IP address it detects, if it’s not the same as your regular ISP then you can verify that it’s using your VPN and not your standard internet connection.
If it were up to me, the first boot I would make sure theres no internet access either via Ethernet or wifi that ensures the computer cannot phone home to its mothership. From there either reinstall windows fresh or straight to Linux if you want to avoid spyware.
I use zabbix to monitor everything, agent on each device uses around 30 mb of memory and with the Linux templates it can monitor just about everything on the server.
You can but sometimes you may run into an error where unarc.dll can’t run and the programs don’t install. I usually use Linuxrulez as those programs are made to work within Linux.
I use Navidrome as the backend and DSub to connect to it. When I’m on the go I use a site-to-site wireguard VPN connection back to my server to listen to music and it also caches the songs so even if I don’t have reception I can still listen to my music.