Pretty sure most large succesful apps have their own UI and UI design teams. Cant remember the last time i saw anything cupertino in an app. Even Apples own 'Home' app only loosely use cupertino. Id say the most noticable effect is the bottom modal sheet slide up effect. on ios the original screen animates into the background a little bit. Apps that dont implement this can be spotted but thats not unique to flutter at all and flutter even offers a pretty good cupertino scaffold package that does this animation.
"cupertino" is the name of a Flutter widget set, not of the native platform controls or L&F.
Few Flutter apps are going to use cupertino because the whole goal of using Flutter is to create cross platform codebases to save development effort. To use an alternative widget set per platform is a huge amount of additional work, and having a cupertino app running on Android is even more of a sore thumb than a material app on iOS.
The two things that stick out the most to me are navigation behavior and text fields. Cross platform frameworks seldom get either right, with react native being particularly bad on the navigation front.
There are variances between Apple’s apps but they’re all using some combination of UIKit and SwiftUI regardless which limits how “wrong” they can be.
You’re completely right, but that doesn’t change the fact that I think it’s a bad idea. For a company that used to care so much about user experience, Apple has been throwing a lot of it out the window in recent years.
