A Follow-Up: The Link Below to Another Forum Post helped me
I was able to get my project to open by copying the TPY file to a place on my computer (under desktop) and then using File–Open in Tropy to open the project from the TPY file from there. Metadata visible. Pictures still stored in OneDrive.
Will I just have to open the project this way from now on, then?
Is there a danger with the TPY file and syncing? Do I have to worry that there are now multiple versions of the TPY file on my computer and in One Drive?
PS: I did not do any deleting of the duplicated files. That’s probably good.