You might want to browse https://caniuse.com/ There are so many features of HTML/CSS/JavaScript that Apple has not seen fit to put into Safari (because, of course, doing so could potentially impact their profits from app sales), but those features exist in Chrome and Firefox on Android. Safari on iOS has become the IE6 of the modern web development era and is really holding us back.
Most features you are talking about are not yet Stage 2 supported. Chrome went ahead and built a lot of these features without full TC29 support. Many service worker features are still Stage 0/1. When it hits Stage 2 safari will gain support.
I think the malice attributed to Apple is somewhat earned due to momentum in the PWA space, but is mostly just do to obeying TC29 stages.
Who cares if Firefox or Chrome on iOS support some new feature if everybody is using Safari since it's the default. You can't ignore half of the mobile market when rolling out your website.
Who actually cares that much about which browser rendering engine they use.
Especially since any new one would likely be almost identical to Safari anyway.