What does this mean? Mac Catalyst is native. It’s just a thin bridge between iPhone’s UIKit and AppKit on MacOS, which are really the only two divergent frameworks in the entirety of the massive Apple SDK.
Also they aren't the only frameworks that are divergent, although that is another discussion.
And no just because the compass is #ifdef’d out when CoreLocation is compiled for MacOs does not count as “divergent”
The various incantations of AI frameworks that have been introduced throughout the years?
SwiftUI vs UIKit vs AppKit vs Cocoa Touch vs Catalyst?
SceneKit vs RealityKit?
I understand as target platform also the various versions of macOS.
Go look at any of Apple’s sample code. Outside of UIKit/Appkit, most of their samples target both platforms simultaneously
Cocoa Touch is just the umbrella term for iOS frameworks including UIKit, and Catalyst also uses UIKit.