I think we all know about mod conflicts when a player tries to connect to the server.
And what if the server directly specified the mod folder where to get resources from, thereby giving them priority bypassing other mods with the same bundles or GUIDs. That is, the steam workshop id would be a kind of key to connecting the mod to the server. And if you have a mod that duplicates the mod, an authorized server, then the player can be launched to the server, but he will need to install the mod that the server specified. And the duplicate would not be loaded.