for me I would be happier with just a basic improvement here
currently in library we have All, Previews & Books
add another couple here for Read & Unread, I have my list in bookshelf mode so don't see what I have already read (list mode shows this but I keep accidentally opening books when scrolling

)
searching and categorising on top of these would be an added bonus
hopefully there will be an update soon, seem to remember last year it wasnt to long after iOS was updated that Vox got some of it