The health of the web as an open platform is defined by browser diversity, not browser choice. As the only major platform that hasn’t been functionally taken over by Chrome/chromium, iOS represents the last real defensive line against Google owning the web.
Remember, you are a web developer, not a chrome platform developer. Don’t be complicit in Google’s slow-moving coup.
The only people who complain about Safari are lazy web developers who fail to appreciate what it means for the web to be an open platform. Testing your website on two browser engines (and accepting that not everything is going to work perfectly in both) is literally the lowest bar expected of you.
Safari is a dirty monopolist on mobile just as much as Chrome is on desktop.