I used Kotlin as well and it just feels off too. The package support is a major thing, as I don't want to mess around in Gradle, I want something that Just Works™. Dart 3 has much of the same feature set as Kotlin now with sealed class support, it's just not as functional, but it recently got tearoffs so you don't have to specify the class, just the property, similar to Swift (ie if you have an `enum Color { red, blue }` and a function takes `Color`, you can just do `f(.red)` not `f(Color.red)`).

The main thing though is that Dart has pub.dev and a CLI that makes it extremely easy to add packages, via `dart pub add`. If I do want to go more of a functional route I'll just use Rust instead, it has all of what Kotlin has and more, plus a similar streamlined package management as Dart in the form of `cargo add`.