Kotlin is better on paper but IMO, only the better choice on Android. I always run into Kotlin tooling issues on "non-android" Java. Stuff like Maven plugins not working. Plus, IDE support is only good in IntelliJ and it's been that way for years so I don't expect it to change.

Kotlin fixes tons of issues in the frankensteined Java 8 of Android. You can use Java 15+ everywhere else and its adopting many features that made Kotlin worth using.

Google is pushing Kotlin so they have control over Android language like Apple does for iPhone. It's just a nice layer over Java in the end since 100% interop is required.