As a beginner I synchronized my files with a sync program to/from my webdav server instead of having it done by Zotero itself. Then I switched to that correct method.
Now I had a look at that server dir content and I am unsure which files/directories on my webdav-server are old and unnecessary ones and could actually be deleted.

My dir on the PC is X:\.....\zotero and there I find the database files and among others a directory \storage\ which again contains my about 900 directories \$$$$$$$$\ containing the corresponding files. I checked adding new directories and files in Zotero and can locate them in those places as expected.

On the Webdav server I find also the expected dir \zotero\
This directory contains a large number of file pairs e.g. XYZ12345.zip and XYZ12345.prop. The age of these files is variable from very recently added to old ones. But the name of the directory of my latest test addition on my PC is not there.
The webdav-server contains also a directory \zotero\storage which contains a lot of \$$$$$$$$\ directories like on the PC again containing files. These directories are 2 months old and that may coincide with my change of syncing method.

Which of the directories can be deleted?
Are the *.prop and *.zip files the correct file pairs deposited by Zotero when syncing file attachments?
Is the dir \storage\etc a remnant of my wrong syncing method?
Thanks for an advice
Franz47