I have the same issue. The import process completes very fast. 2000 photos in 10 seconds.
However, no photo is imported to the library.
I hope apple developers aware this issue, and it is fixed in the next mac os beta release.
I had Photo import and iCloud issues as well until I resorted to a new system PhotoLibrary. After pointing to a new PhotoLibrary, the import/iCloud worked perfectly
Still an issue - iOS 12 on iPhone SE, Catalina on Mac - import pretends to work but does nothing - created new album, still nothing imports. Cannot get photos off of phone using Photos.
Hi. Has this been resolved already? I've got the same issue and really need to backup my photos. Working on the latest operating systems.