You can have calibre auto import from a folder. Though be careful because it deletes them from that folder (you might want to do single direction sync into that folder).

And if you share the db with calibre-web or have some other sync method that works, you should be good to go.

Yes, they share the database. Yes, I add the books to calibre. I think I have it as read only for calibre-web.

Regarding overcomplication, I admit the initial setup took a while. But I’ve had it running for a couple years now with no major issues.

There’s a docker that essentially sets up a web VNC for Calibre. I do this for file conversion, DRM removal (only books I buy), etc.

Then I use Calibre-web for the OPDS server and nice web UI.