[unit_circle]

Neither are exactly a 1:1 replacement, but check out backblaze and syncthing. A combination (syncthing for device sync, backblaze for offsite backup) might suit you.

I was impressed with syncthing when I used it ~2 years ago and I assume it's matured since then.

[alwayslikethis]

The only issue with syncthing is that it is prone to conflicts if you modify from multiple devices (such as some notes from phone and laptop) and you don't have at least one device always online syncing. For offsite backup, Hetzner has some very cheap storage boxes.