I really don't understand why you won't see th eplugins that you place in your plugin folder.
do you have multiple copies of PinballX on your system ?
Do you see the 4 DLL's for the plugin that are coming with the installation in the plugin folder?
If I copy a plugin dll into the plugins folder
and run Plugin manager :
So sorry, to ask, but you sure, you unpacked the dll to the correct folder (and not place the zip)?
Is the DLL unblocked ? See Unblock .dll file | Blog | Limilabs
are access rights correct on the file (no access denied to user or system account) ?
If this all is not working, and you move for example ledwizz.dll to another folder, will ledwizz disappear from your plugin manager?
I really want to help, but not sure what is going on, on your PC