For example this page works fine in Safari

https://fonts.google.com/specimen/Nabla

Both MacOS and iOS.

The expectation that every user get's exactly the same experience regardless of what browser they're using has held the development of great user experiences on the web back for about two decades now. There's no reason why you shouldn't deliver a better experience for some users if their browser is more capable.

Design a working minimal app. It'll probably be close to a plain HTML and CSS site that's rendered on a server. Then add in things that make it nicer to use while checking that the browser supports that feature so you don't break anything if it doesn't. Build up to a really nice experience. Progressively enhance the usr experience. This is literally how websites were built 20 years ago, but then developers got lazy and only wrote apps for the lowest common denominator, which meant any new features in browsers rarely good used, and at the same time slightly unusual browsers like Lynx got abandoned entirely. It really annoys me.