Attaching Safari Dev Tools from a Mac to the iOS device should surface those errors, in my experience.
They release new API but they "forgot" to test when website is added to home screen (PWA).
New API passes feature detection but does not work in PWA.
iOS and macOS Safari have different bugs also...
So you have to sniff user agent and other things to find out broken iOS versions and hardcode workarounds...
In either case, there are plenty of browser testing SaaS that give you real Mac/Win/Linux/iOS/Android machines for testing and debugging.
https://developer.microsoft.com/en-us/windows/downloads/virt...