For anyone who is not familiar already:

Calibre is a desktop application that has some file hosting/syncing features.

Calibre-Web is a server software that uses the Calibre library files, but can operate independently after setup.

Calibre Web Automated is a server software based on Calibre-Web with an overhauled UI and many additional features including automated ingest, OIDC, KOsync, file conversion and fixing, and more.