Who is this mythical end-user with an old browser? Because they don’t show up in browser usage statistics.

https://gs.statcounter.com/browser-version-market-share

Chrome is evergreen, even on Android. Safari, after a bit of a fallow period, is updated fairly aggressively, and though it’s still coupled with OS updates, it’s no longer married to the annual x.0 releases.

Mind you, I still believe, and practice, you should write semantic HTML with progressive enhancement. But at the same time, I absolutely do not think you should go out of your way to test for some ancient version of Safari running on a first-generation iPad Pro—use basic webdev best practices, and don’t spend time worrying that container queries aren’t going to work for that sliver of the market.