I find the Paperwhite 1-3 chassis to be quite solid. Prior to getting a neoprene sleeve, I just had it caseless in my purse with the front (raised) bezel against something flat (usually my iPad in folio case) so the display doesn't get nicked by keys or something.
That said, Kindles don't have built-in article syncing like the Kobo and they don't support EPUB.
Since you love the Clara, if I were you, I'd just get another Clara HD and use a more protective case. Maybe a zippered hard clamshell case like this for carrying around in the bag.
https://www.amazon.com/USA-Gear-Elec...dp/B078TLSZ9T/