Again, that’s a side-issue and not even important. If one can SET the local PC folder manually, you can change it there when you have changed its name or location, which would solve it.
The main issue is that denon re-invents a file-system and directory structure on its controller storage that should not be needed at all. Just copy-paste the main folder from PC to a main folder on controller storage and all issues are gone.
Use both for syncing, use the PC folder as master, so you are always able to change audio-content on PC and then sync when you’re done with them.
EngineDJ only needs to keep a database for metadata, for keys, BPM, stems and link that to the audio-files in our user-chosen location, both local PC as well as controller storage. Problems solved.
WHY place audio on controller storage in a different dir structure? What use is that? Completely useless, failure prone, extra point of failure for software on both ends, as far as I can tell it’s a mistake to code it like this. Probably derived from laziness, to make it ‘easier’ for the coder to link audio-files to metadata (BPM, key, stems etc.) the coder decided to re-invent his/her own file-system on top of the existing one. Causing nothing but trouble, delays, complexity for us users.