Just closing up on this issue here.
I worked with support, and though their suggestions in dealing with the shared folder transition issue were valid, at this point in time what I was left with was a correct shared folder setup (correct names pointing to correct disk folders), but the data that remained was in folder 'Shared" and not. “Shared_PriorTo_2025-05-27”. So I SSH’d into the unit and moved the data from “Shared” to “Shared_PriorTo_2025-05-27” from the command line. Much faster and safer than in file station.
All is good now. Got my archive data stored in “Shared_PriorTo_2025-05-27”, and started a new one-way sync from my other NAS to this NASes “Shared” folder.
Closing this out.
Thanks for all the suggestions.