I am not a tech guy nor a UI specialist but I don't see why WP should have a PDF creation that looks like the printed version of a page and a printable version of a page that doesn't look a printed page. When you have Chrome it gives eventually the same result but not with Firefox, Brave or other browsers. Should the printable version of a page not generate and propose its PDF version automatically?
Moreover, creating human readable books obviously requires specific tools that go beyond a simple PDF rendering per page and the collating them. I would separate these two topics.