Remote transfer of selected folders & files from PC to a MyCloudEX2Ultra

I have a MyCloudEx2Ultra drive connected to the internet at a remote location. I want to sync selected folder structures & files from a USB hard drive connected to one of several PCs, to the NAS drive, or vice versa. Currently, it seems I must use MyCloud Web to access the drive, then manually recreate the remote folder structures, then manually copy one folder’s contents at a time. Obviously, this is not a reasonable approach for a large number of folders and files. What is the best way? I do not want to setup a dedicated Desktop Sync on every PC I use. My ideal situation would simply be to map the NAS drive locally, then use Total Commander to sync selected folders (and sub-folders & files). But I do not see a way to map, or even access, a remote NAS drive.

You could refer to this article: