I've used
zfs-auto-snapshot (
https://github.com/zfsonlinux/zfs-auto-snapshot) for years, but for some reason I've long disabled it in OS X. My Ubuntu and Proxmox servers run fine with it.
To make a long story short, based on advice from this forum, I tried
znapzend on my Mac running the latest Big Sur / OpenZFS over the weekend, and was really impressed: it can be installed either by Homebrew, or via the GitHub page (
https://github.com/oetiker/znapzend - ran into some permissions issues in the end, but opted for that).
Of note, it creates snapshots on the source dataset, but also replicates (via zfs send) to a backup location.
It was a revelation to update the backup of a 40G file (that used to take a loooong time with rsync) in just a few seconds!