Unable to see documents when searching by folders in Modern Document Libraries

5 years later, here I am reading about this very same problem still persisting in Modern SharePoint. My experience, refining a search with the Path: key, if you search the entire Site and Document Library path, all files are returned from that Document Library. But as soon as you tack on the name of a root folder, the search results simply return that folder and none of the files within that folder.

It's extremely frustrating to find that this limiting search behaviour still persists, even after being reported 5 years ago. 😢

Keen if anyone has any suggestions for searching a Document Library (and to not use any folders isn't an option here).