Cockpit
I do know about and use Cockpit with said virtual machine manager but I mostly use it as a shutdown/boot/restart app in my phone and a convenient service monitor and log viewer when troubleshooting.
Wireguard/OpenVPN
I really should try out Wireguard sometime but currently OpenVPN is fast enough for my bandwidth and I was already proficient with setting it up before Wireguard.
The WebUI definitely looks useful.