Clara HD Sync Kobo Clara with Synology NAS

After buying a book from the kobo store, the sync button on the kobo reader will sync the book with the reader. I am looking to set up similar functionality with my NAS (a Synology DS418), that is: when I press the sync button on the reader, it will pull all books that I put in a specific folder on the NAS to the kobo device. Would that be possible?

PS: I am aware of content servers such as Ubooquity that can be run from the NAS, but these do not offer exactly what I want because this requires 1) the content server program to run and content to be actively updated, 2) the content to be accessed via the non user friendly kobo browser, and 3) the software to be stable, which it isn't. Instead, I want to be able to copy files to the NAS folder and then control the syncing from the kobo device.