Not really automation, but I will copy-paste a comment I made in an older thread, maybe it can still be useful :)

• I download books through Z-Library, I tried in the past lazylibrarian and readarr/bookshelf for automation, but I always ended up spending a lot of time on refining the search for non-english books or specific editions, which was just way easier in Z-Library.
• I tag/update metadata of books using Calibre of my laptop. I prefer to manually do that because while it took a few days to do it for my whole library, I don't really add books in such a high number that I can justify automating it or having a Calibre container on my homeserver. (I know Calibre Web Automated will do this, but see below). I use Hardcover to track my readings, so Calibre with the hardcover plugin makes it easy to find ids or HC editions for integrations with other apps I use.
• After moving between Kavita, CWA and Booklore, I set up on Komga for library management. I found Komga's koreader sync way more stable and mature than the other options. I am a bit annoyed by the fact that (as in Kavita) each book/series folder is a series, but at the end of the day the pros outweighs the cons for me. I can manage custom reading lists or series, so it's not really an issue personally.