If you’re using UniFi, Teleport is a solid option. I have a couple devices that can’t run teleport like a travel router so I just use WireGuard.
Another option that people use a lot is Tailscale but it’s a service and not self hosted.
If you go the ZFS route, you could check out syncoid.
Some other tools that might be worth considering (that aren’t related to ZFS) are borg and restic.
Hope that helps.