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.
Meh. I pondered this but leaving it helps users still using the platform.