“Remove unused Javascript”

The unused CSS/JS is being reported as being Autoptimize’s, but AO merely aggregates all the CSS/ JS provided by your theme & plugins, so if you (really) want to tackle “remove unused CSS/JS” then you should look into your theme & plugins (you might be able to get some improvement using e.g. “plugin organizer” to only allow plugins to work on specific pages). Moreover the unused CSS/ JS will likely be different for different pages (or parts of your site), so that would lead to different autoptimized CSS/JS-files being loaded on different pages.

hope this clarifies,
frank