The difference is Apple OS updates on older devices don't always have all the features the new OS gets on newer hardware (which makes sense in many cases) while older Android phones can run most of the latest updates to Android (e.g., Jetpack Compose)

A SwiftUI app vs Compose app right now is night and day, bugs from iOS 13.5 to 13.6 are catastrophic meanwhile Android devices with extremely old operating systems run the latest UI toolkit with very few issues.