I've worked in several JVM backend projects, and Kotlin has been a stark improvement over Java (at least up through version 17, the most recent with which I've worked directly). Compose, and Compose UI, are tremendously promising technologies; I've shipped desktop apps with Kotlin for multiple platforms, and compared to just about every other desktop UI framework, it's a clear winner in terms of productivity and an ability to GSD.

All that to say, I believe that Kotlin has a lot of value, independently of Android.