Still unable to copy some essential files in the PMS folder!
So I finally managed to do exactly what you describe in your previous post. So I have a shared folder that points to the original PMS data folder inside the ‘.qpkg’ folder and it now shows as containing close to 16GB of data which reflects it is phyiscally accessible while I previously I only had that ‘PlexData/Plex Media Server/’ placeholder whith was a few kb in size (but also showing the full content of the PMS data folder in File Station).
FYI, I had setup Plex on my QNAP NAS according to [these instructions].(PlexData share for QNAP systems)
Here’s an animated gif demonstrating the problem.

Please help!