In my opinion, iOS 5 was the peak for iOS, iOS 7 is where everything went off the rails. Present-day iOS has a notch, a screen with rounded corners, no home button, and endless places on the screen that are swipe-able.

Haven't used OS X since Mojave, but compared to Jaguar, there are no scrollbars, the interface is designed more for a trackpad instead of a mouse. The peak for OS X in my opinion was the Panther/Tiger/Snow Leopard era.