My work flow is pretty similar to yours:
For my desktop and laptops: systemd timer and service that backups every 15 minutes using restic to my NAS.
For my NAS : daily backup using restic + ZFS snapshots.
All restic backups are then uploaded daily to Backblaze B2.
Only restic snapshots are backed-up to B2. ZFS snapshots are for undoing mistakes, though I enabled them recently and I have yet to use them.