- SVG background issue from 2016. Tested on my Safari Tech Preview 113 (Sep 2020), can't replicate.
- Clicking issue. This is related to mouse event bubbling on iOS only (will affect both Safari and Chrome since they both use the same WebView). It's theorised that Apple set a specific set of rules when mouse events (on touch devices) will bubble up for performance/usability. Or it's just a bug.
- A rendering issue from 2012. It's explained in your link this is related to pre iOS 7 era performance improvement by WebKit to only redraw those parts of an image that have changed. Sounds like a very reasonable thing to do, taking into account how Apple heavily pushed performance and battery savings on mobile/laptop devices a decade ago.
- Round Corners. Tested on my Safari Tech Preview 113 (Sep 2020), can't replicate.
I don't see how any of these are anywhere close to being "total nonsense", feels like you're being biased and just exaggerating on purpose to bash Safari.
Chrome force logging in you when you use Gmail to hijack your privacy and link your browser history to an account sounds more "nonsense" than Apple focusing on performance/battery on mobile devices a decade ago that created a regression/new bug that requires 1 line to solve. https://news.ycombinator.com/item?id=17942252
I primarily use Safari for privacy/battery/performance reasons, and on my web app of 2 years with tons of styling I have 5 lines of scss code with "// safari" comment to make some elements render the same as Chrome.
Never in my career writing a single digit line of additional css made me think "oh my god this is total nonsense". Everyone has to accept there will be differences from one browser engine to another, and from my personal experience, these are minimal and nowhere near IE6 back in the days.