It also cannot re-tag (just rename) - because in case it did grab something, this would break torrent hashes.
Learn how to setup Atomic Moves https://wiki.servarr.com/lidarr/settings
Lidarr will tag&rename anything you want, but still keep the original torrents untouched, because it will hardlink them to a renamed filename were you want and at the same time it will keep seeding. The physical file will be linked from 2 different folders, one of which is the torrent download folder and the other is your library folder. 1 file, 2 links.
Can you link some tutorial about this? I don't need it now, because I have a Kobo N514 with 32 Gb microsd, but if/when I decide to buy a new one, I'll be forced to use your method. I already have all my books on a server on both Kavita, Ubooquity and COPS, so I just need the Kobo configuration part I guess.