PWA could have been awesome but Apple and Google would rather have apps in their stores where they can clip the ticket. Sad.
*Apple
Google for the longest time was (and still is) one of the biggest supporters of the idea. Chromium overall has the best support for PWAs and some of their Apps (like Google News or Photos) have very competent PWA versions.
Samsung’s OneUI handles PWAs much better than stock Android. What Google does is the bare minimum.
Not from my experience. Almost all Android Variants (including Stock) handle them great.