Sync-in behind VPN?

[Stephan-P]

My sysadmin at work has strongly suggested that I'd reduce internet exposure of my NAS and container apps and place them behind a VPN; Wireguard or Tailscale or Headscale. Something similar had been suggested to me before by other people as well, so I gather this makes sense.

I've done research on Wireguard and Tailscale, and its open source alternative Headscale and its companion UI Headplane.
But now I'm wondering if Sync-in (and Collabora Office) can work through a VPN tunnel, as their configurations make references to regular open internet urls?