Sync with a network drive Dropbox versus QNAP Sync App

(as suggested by a superuser on one of the other Dropbox forums, I should post the question below in this API Support forum, the original question was posted here : https://www.dropboxforum.com/t5/Syncing-and-uploads/Sync-with-a-network-drive-Dropbox-versus-QNAP-Sync-App/m-p/232473#M29356 )

I've a small LAN, and a QNAP NAS. I need to access files from projects on my Dropbox, from different workstations, laptops, PC's, Servers.

Because not all those machines have a TB free on disk, moreover it also seems highly inefficient space usage having the same 500GB of files copied on every machine.

Now Dropbox does not support storing the Dropbox data on a network share on the NAS. Telling me that I've to use the QNAP App to do that. Which I've no problem doing, HOWEVER, at the same time, Dropbox is restricting a long list of files, so they cannot be synced through 3rd party apps, but they have no problem being synced through the Dropbox app. The restriction/blocking is not done by QNAP, but by Dropbox (the API).

This way, Dropbox seems to take the situation hostage, preventing us from storing our dropbox files on our own NAS.

There is no logic in the restricted files, a few DLL files,  a few ZIP files, some JS files (for example ... why is it not allowed to sync "jquery.js" ?), some EXE files (freeware!). After the QNAP app had synced about 100GB, I already had > 20 files reported as restricted.

Where does the discrimination come from? Why is there no issue with the Dropbox desktop app, but are there restrictions for 3rd party apps? Why am I not allowed to sync my own files on my private storage?

Is there a solution? How can we sync Dropbox and a NAS?

Thanks,