For Macs: I use Time Machine backups on unraid (nothing fancy but it has built in settings to support it effortlessly). There’s also https://hub.docker.com/r/mbentley/timemachine that I tried out a year ago.
I haven’t tried over vpn but as long as you can mount the share , it should be fine.
They recently broke hwid, but was recently fixed as of 2.2. The other method worked fine still