Note that Alex Russell is a Blink partisan, currently supporting Blink at Microsoft and formerly having done so at Google. Folks like that don't take kindly to the idea that a Blink monoculture might not be a great thing, and definitely do not share the opinion that it's critical to the open web that Apple not cede the open web to Blink.
Remember, Blink began as Google's 2013 fork of WebKit. They've embraced and extended it, but thankfully the "extinguish" step is taking longer than they thought. This makes the "open web, as long as it's my engine" people upset.
Safari's PWA support is not as complete as Chrome's today, but it's as good as Firefox's support and perfectly capable of supporting rich, standards-based apps. https://pwascore.com/
The fact that your "argument" rests upon baseless ad hominem, I'm mostly inclined to not even respond.
I'll simply say that if you bothered reading anything (let alone objectively), you'd clearly see that no one is arguing for a blink monoculture. They're arguing for allowing everyone to choose whichever browser and browser engine that you want. Safari included.
The math isnt mathing on that site... And, no, safari is NOT capable of PWAs - which is the primary point of contention (not obscure APIs, though safari generally lags in all of that as well). They deliberately hobble PWAs and make them very difficult to install.
edit: also, your site is just obviously biased/poorly done, because there exist many better comparisons of web features, which show how vastly far behind Safari is, often even of Firefox. This is unsurprising given your chosen style of rhetoric
https://wpt.fyi/
https://webstatus.dev/