Thank you very much for your help so far.
I should probably add that I made no further changes to Truenas after I realized my mishap. I immediately shut down the NAS.
I found an article online that explains how to recover a dataset, but before I do something stupid, I’d like someone to evaluate this article in terms of its usefulness with Truena’s Scale.
https://endlesspuzzle.com/how-to-recover-a-destroyed-dataset-on-a-zfs-pool/
Otherwise, there’s Klennet ZFS Recovery, a software I stumbled across in several threads dealing with the same topic. Useful?
I assume the ability to recover via zpool checkpoints is not yet available, is it?