I think you could potentially do this using Calibre-Web and some scripts. I have not personally tried this (although I do use Calibre-Web), it's just an idea I think could work although it may be kind of convoluted. Calibre-Web is a web service that runs on top of a Calibre database. One of the things it can do is sync with a Kobo eReader.
You would set that up, set up a script for automatically adding books from a given folder (
https://github.com/janeczku/calibre-...w-books-(Linux)), update the shelve of the news books to be news so they end up in the news collection (
https://github.com/supfors/c2cw_shelf_sync).
I am not sure there is any way to auto delete books from the Kobo however...