Next JS has a starter kit for a few different platforms called nextjs commerce - https://nextjs.org/commerce

Getting to PWA would probably be pretty simple since you just need a service worker to qualify if I remember right -- https://developers.google.com/web/ilt/pwa/introduction-to-se...

Making PWA valuable and doing things like prefetching pages would probably be a much bigger task but is really incredible to see live from a performance perspective. Here's a headless commerce-enabled PWA with prefetching to see what I mean. https://discountelectronics.com/