I returned to my company where I had initially followed the deployment of EPDM.
Many people have followed one another and everyone has changed the management structure a little as they wanted/thought.
So now I want to put this all back in place.
Initially, the idea was to have a "LIBRARY" folder with all the SolidWorks and SolidWorks files.
Subsequently, we separated into "Assembly", "Parts", "Plans", "Others" (DWG, STEP, ...) because the loading when opening the "LIBRARY" folder was long.
Since then, many files have been created "Commercial parts", "Screws", etc.
What worries me is that each employee has to ask himself or herself all the time the question of where to record, which was not the case initially. This was done in order to find the files more easily , like on a Windows server, but this is not for me the philosophy of a PDM.
For me, it is the search (via number and/or data card variables) that should allow you to find your file and not the different folders.
I would like to go back to a single "LIBRARY" folder, which would also allow you to automatically open drawings of an assembly or part in SolidWorks, which is no longer possible today.
You say that you were forced to split the "LIBRARY" folder because of the loading times, so you have to keep a minimum of tree structure.
It may be interesting to keep the "SCREWS" and commercial parts files (perhaps classified by Manufacturer and not by seller). In the latter case, it allows you to do an "intuitive" search, it is by seeing a manufacturer's name that you think that it can make the part you are looking for.
For the pieces created, I imagine that they are identified by a number, so I will start with a numerical tree by slice without worrying if it is asm or prt (Of course, you have to keep the drw in the same folder as the model). It will then be easy to test the response times according to the number of files present and possibly split the slices or merge them.
I'm neither an EPDM user nor an administrator but I know (thanks to this forum) that you can do a lot of things with it.
You have a double problem: users and IT performance, which are sometimes antagonistic. I think that nothing prevents you from having a tree structure for storage that we know will improve performance and "limit" user access. When I say "limited", it means that users, because of the unique numbering, have no choice but to go through the EPDM interface. I imagine that it must be possible for the saving of a new file to be managed by EPDM to be done in the right place.
For the manufacturers, it was an idea, given your case, it is obvious that it is not suitable. And if the file names of the screws and the trade are identified like the others, at that time, I will just stay on a tree structure by number range just for the perf.
To confirm the statements of @YP69 without PDM, our library is also divided into categories (training, positioning, etc.), all inspired by the categories of Emile Maurin's library, and newcomers and subcontractors understand without explanation or looking for their pieces, which justifies these categories.
We also had the same approach at home for libraries. For the rest, we have a file for unit plans, a file for purchased sub-assemblies.
The display times of the contents of the folders have been improved on the different versions of PDM even if it is not at the level of a classic Windows folder access (whether on a server or locally).
After that, it is true that it all depends on the corporate "culture" and the habits of the users. For PDM we should be able to be satisfied with the searches but this requires a correctly populated database to have conclusive search results.
At our company, it's been 10 years since we deployed PDM and the search to find library elements is not optimal because our users only fill in what is needed for 3D (custom properties) and not what could be needed for a search (data map fields not mapped with file properties).
As a result, the file strategy is totally adapted.