It’s hard to boil this down into a nice neat title. 
I use zfs on Proxmox, Nextcloud, TrueNAS, and standalone in a DMZ. Each of these sources snapshots locally with at the very least daily frequency.
I use syncoid to back the Proxmox boot images, the Nextcloud files and DB dumps, TrueNAS boot images and a standalone DMZ share up to server1 which has a number of additional CIFS and NFS shares for personal files, media, etc.
Everything works beautifully up until this point. What happens next is more of an inconvenience, but one possibly easily solved.
I then back up the entirety of server1 to server2 via syncoid. The datasets that originate on server1 replicate without any issue. The datasets that were daisy-chained (Proxmox, Nextcloud, TrueNAS boot and DMZ) have had their older syncoid snapshots overwritten on server1. That is not an issue because server1 and server2 share the previous day’s daily snapshot and that is used to replicate the changes until now. That replication also overwrites the older syncoid snapshot on server2.
The frustration is that syncoid throws a bunch of warnings when it then tries to delete the older snapshots.
Sending incremental primary/Backup/boot-pool-Scale-22.12@auto-20230903.0000-2w ... syncoid_truenas222_2023-09-04:04:00:34-GMT-04:00 (~ 4 KB):
could not find any snapshots to destroy; check snapshot names.
could not find any snapshots to destroy; check snapshot names.
WARNING: zfs destroy 'primary222/freenas1/Backup/boot-pool-Scale-22.12'@syncoid_truenas222_2023-09-03:08:09:49-GMT-04:00; zfs destroy 'primary222/freenas1/Backup/boot-pool-Scale-22.12'@syncoid_truenas222_2023-09-03:04:00:11-GMT-04:00 failed: 256 at /usr/sbin/syncoid line 1596.
Sending incremental primary/VM_Backups/NextcloudData@zfs-auto-snap_frequent-2023-09-03-0030 ... syncoid_truenas222_2023-09-04:04:02:43-GMT-04:00 (~ 18.2 MB):
could not find any snapshots to destroy; check snapshot names.
WARNING: zfs destroy 'primary222/freenas1/VM_Backups/NextcloudData'@syncoid_truenas222_2023-09-03:08:12:23-GMT-04:00 failed: 256 at /usr/sbin/syncoid line 1596.
Sending incremental primary/VM_Backups/NextcloudDbBackups@zfs-auto-snap_weekly-2023-09-03-0015 ... syncoid_truenas222_2023-09-04:04:02:54-GMT-04:00 (~ 40.8 MB):
could not find any snapshots to destroy; check snapshot names.
WARNING: zfs destroy 'primary222/freenas1/VM_Backups/NextcloudDbBackups'@syncoid_truenas222_2023-09-03:08:12:25-GMT-04:00 failed: 256 at /usr/sbin/syncoid line 1596.
Might I suggest possibly using a dataset property like the syncoid:sync one so that I can set a flag on those daisy-chained datasets and syncoid knows not to complain about snapshots not be able to be deleted.