How to implement Snapshot Replication

I have data on several machines that I want to backup in away that I can restore to certain points in time.
From what I read Snapshot Replication achieves this (as opossed to back-up that clobbers previous results).
The main motivation is that if the data files are ransacked, and encoded, then if I just back-up I can end up in a state where the backed up files are also encrypted.

One way to do this is by using 2 Synology NAS machines where I can have:

rsync processes to back-up files from multiple machines into a NAS1
apply Snapshot Replication from NAS1 to NAS2

In this way, if the data is hijacked at certain point, I can restore the data to the last good state by restoring NAS2 to previous point in time.

I would like to know if:

Snapshot Replication is the way to go, or there are other solutions?
are there other ways to achieve Snapshot Replication, e.g. with single NAS?

I have an older Synology 2-Bay NAS DS213j.
Assuming that I buy a second, newer, NAS (e.g. DS220j), are the 2 NAS machines expected to work together?

Thanks

Solution

I found out that Hyper Backup can save snapshots in time, so I'm using it instead of Snapshot Replication