A PWA is a Bigger Investment than AMP as a Solution for Improving Mobile Usability
Make Sure A Separate PWA is Canonicalised to Your Mobile Site
Google won’t get confused between your main site and separate PWA as long as you have canonicalization in place.
John Suggests Considering a PW-AMP Set up – a PWA Combined With AMP Content
Google have been looking into a PW-AMP set up, combining a PWA with AMP content. John suggests this combination is something worth looking into.