Im working on a similar project, Colibri (https://github.com/colibri-hq/colibri), an app to manage your ebook collection. Librari is looking really slick! Also, It’s always interesting to see how others approach schema selection and customization.

If I may, I would suggest adding support for ingesting data from open sources, for example OpenLibrary, WikiData, the LoC API, and a bunch of others. Since you’re building a for-profit project, you can probably also tap the billed services to get high-quality metadata. But even with OpenLibrary alone, you have access to a treasure trove of information that spares users from having to type off things from their books. That allows for bulk import, high-res covers, and so on.

I’m currently working on the metadata reconciliation engine in Colibri, so feel free to check out the source every once in a while.