Have you tried Brave browser on mobile? It's quite fast and blocks ads.

A couple issues with Safari I've seen since it's slower to adopt web standards:

- buggier websites from devs who don't have iPhones. Since there are some quirky inconsistencies with how webkit handles css vs other browser rendering engines it's easy not to catch those quirks if you don't have an iPhone to check them with. And once users point them out, it's a pain to fix without a physical device.

- a smaller web feature set than chrome/Firefox. For instance, Safari doesn't allow localstorage while in incognito. I think it supports serviceworkers and webrtc now but it took years to get them.