If the issues here are on the server side, maybe Kobo should create some sort of control panel to the user account on the website where users can do some very basic book management, like
- creating/deleting/renaming shelves
Reading preferences
- which book categories you like and don't like (and don't get book recommendations of book categories you're never gonna buy)
- which book languages you want to recieve offers/recommendations in.
Modifications will be synced to all devices.