Assuming you installed Duplicati the same way this time, the Database screen shows the location.
The job database name (not folder) is random and new with the import, but the folder is the same.
For non-service install, it’s usually in %localappdata%\Duplicati. Easiest migration is to preserve it.
If it got wiped with Windows, then the only source of history is the dlist files. Have any old ones?
Direct restore probably looked at the latest. Any chance that the configuration changed over time?
Looking over old dlist files is the lowest level way to see if your folder is in the filelist.json file.
If you don’t encrypt, then you can just unzip, and probably notepad will let you search file (crudely).
Do you have lots of versions? There are other ways to do this, but all of them are kind of awkward.
For example you could make a dummy job (don’t backup or do dangerous things) to recreate a DB.
You can then either look at it in a DB browser, or set all-versions and run find in GUI Commandline.
EDIT:
How did you do that, and when most recently? Maybe there’s an old backup version that looks better.