You can run Kodi Headless in a Docker Container, and configure it use MariaDB on the Synology. Use the headless Kodi instance as your scraper and library ...
I run kodi with a central DB on my syno nas with maria db. Now a major update is coming from 7.1 to 7.2 (dsm) I saw that problems where on my way with that one.
This package mounts an iOS® device (connected by USB) to a shared folder of your Diskstation. You can access such folders locally or from remote with Synology ...