How to mirror tags update to library?

Yes, this is quite perfect!

I can only recommend you to always:

  • stick to the recommended folder strucuture: ...Lossless/AlbumArtist/AlbumTitle/tracks
  • always check embedded meta tags before adding new files. Of particular importance is the AlbumArtist meta tag. It must be present in all tracks of an album and must have identical content. The “Track Number” tag must be present in all tracks of an album. If there is more than one disc in the album, the “Disc Number” tag must also be present in all tracks.
  • prepare new files outside of the Plex media folders (those folders which have been added to a Plex library). That includes naming the files, preparing the folder hierarchy, and also inserting or modifying the embedded meta tags.
    Don’t employ the strategy “add first to Plex, only if things go wrong start investigating and cleaning up”.
  • Don’t tell plex to automatically scan its libraries, nor let it scan them periodically. The risk that a library scan is started before all files have been added/copied is too high. Always copy all the files first, only then start the library scan manually. Don’t start library scans in rapid succession. Never let two scans happen at the same time.
    Monitor the server activity icon https://support.plex.tv/articles/200871837-status-and-dashboard/ in the web app to verify that the server is not busy with a library scan, before starting a library scan.

As I said above, if the change to the meta tags leads to a change in the structure of the library (i.e. albums changing artists, or tracks swapping albums) then you won’t sometime be able to avoid the Plex Dance.

Since you are using a QNAP device: Don’t use the pre-existent Multimedia folder. This should only be used for the default QNAP apps, but not for Plex.
See Q14 of the QNAP FAQ: Qnap faq.....read me first!