Using snapshots on a copy-on-write filesystem such as zfs or btrfs is actually a very good idea. There exist auto-snapshot services that are quite easy to set up and take snapshots with different granularity and maximum number of kept snapshots e.g. every 15m, hour, day, week.

Please note that even snapshots and RAID never replace an off-site backup. When setting up Nextcloud I was even so paranoid and configured the backups to be pulled by the remote machine where they will be stored (and the Nextcloud machine does not even have credentials to access it).