i think kotlin has more use outside compared to swift.
But a language has to start somewhere, so i wouldn't hold it against swift. It's a fairly well done language regardless, and nothing apple specific about it tbh (which are all just libraries).
It was JetBrains pet project to fix archaic stuff in Java without making a Scala. It was designed from the get go for a wide base (as wide as java).
I'm not sure how it became Android's main target, but I doubt it was the original purpose.
Honestly the only times I've evaluated Kotlin for personal projects was bc of that flexibility.
If that was the case, they would have adopted Dart instead of keeping an high dependency on the Java ecosystem for Android.
Android Studio, Gradle, Kotlin compiler, the libraries that Android depends on from Maven Central, all Java.
Try to use Kotlin without the Android ecosystem, it is just syntax sugar for the JVM.
I agree and would go so far as to say that Dart is a better comparison to Swift than Kotlin is.
It helped a lot that I think Jetbrains took advantage of all they could to make development in Kotlin very smooth, I remember back then people joked how Kotlin worked so flawlessly on Android Studio almost like it was the main language while on Xcode Swift was slow, the highlight would stop working constantly, refactoring was not supported, often indexing the project would hang forever etc.
Hence why Kotlin only really matters on Android.