Think of something as simple as the lock screen.
On the iPhone and iPad, it’s an area that can be heavily customized. You can put shortcuts on the bottom of it, it houses all of your notifications, it has widgets, it has different clock styles, it has live activities.
On the Mac it’s… just where you enter your password. It has the benefit that you can put a moving screensaver behind it, but besides that, it’s literally just for logging in. No extra functions, other than logging in it’s basically completely useless.
Or the Notification center, iOS has long ago moved away from using the notification center to how’s widgets, that’s something back from the iOS 8/Yosemite days that the Mac hasn’t caught up with.
Or in several of the built-in apps, there are just functions and interfaces throughout the operating system that are inconsistent in ways that go way beyond just being different designs for different form factors.
Think the Apple Music app, the Apple Music app on the Mac is a completely different beast from the Apple Music app on iOS. There really isn’t any reason for them to be that different, yet they are. There are Apple Music features on the iPhone, completely missing from the Mac, and even more features on Apple Music for the Mac completely missing on the iPhone.
Your examples don't help making the point you're trying to make, at least for me.
1) Lockscreen/Notification Center/Widgets. I'm a minimalist, I don't actually like the extremely cluttered and customized lock screen on iOS and I very much do not want to see something similar on macOS. The lock screen should be that, a lock screen. It shouldn't display any sort of - possibly even private - information for everyone to see who just happens to open up the Macbook. That's the whole point of it being, well, a lock screen. It doesn't need - nor should have - "extra functions". Especially not on a mac. In contrast, I kinda miss the old iOS where there weren't a million different ways of getting the same information (notifications being shown on lock screen and notification center, e.g.). It makes it cluttered and actually more confusing, because while some information are accessible through different means, others are not, and it's very much not intuitive which applies to which.
I'm also oldschool enough that I STILL dearly miss the macOS dashboard.
2) Music App. The music app on macOS is basically the rebranded iTunes app. Long ago, Music and iTunes on iOS used to be separate apps altogether. I'm genuinely curious what specific every-day features are missing from Apple Music on the Mac that exist on the iPhone, and vice versa.
Don't get me wrong, I'm all for consistent functionality, even mirrored functionality where it makes sense. But that has very little to do with UI and also does not need to be forced on every single individual feature just for the sake of it.