btrfs and zfs tools have no build-in option for batch-deleting of snapshots and setting restrictions.
This script is intended for deleting multiple specific snapshots from a greater amount of snapshots. For example delete all daily snapshots and keep the weekly. Or delete snapshots from a specific day.
delete-subvolumes -m btrfs | zfs -p $PATH | $DATASET | -r $RESTRICTION -d (only show output, not actually delete it)