They actually have a (very new, still alpha, probably not a ton of data yet) database for books:
I haven't looked into what their schema is like, but if it's anything like Musicbrainz it will be pretty comprehensive and easy to pull the data you want out of!
That's the post I made on r/plex a decade ago that pissed off a dumbass moderator and got me banned from there! I guess he hated books.
I've recently been doing data entry on Open Library... sometimes even worldcat doesn't have an OCLC for an edition, and Open Lib is my fallback. Maybe I should be doing it on Bookbrainz instead.