Is Java or Kotlin the best future programming language?

No, if only because neither of the two is a future programming language. Java is 30 years old, Kotlin 14.

Also, why would you think that’s the best we can do? Even only considering languages that primarily run on the JVM, I would rate scala 2 higher (don’t have much experience with scala 3; it may be better bit it looks quite different and it takes time to get used to it)

LLMs generate Java better because of so much more enterprise quality training source code and ingested coding textbooks.

The future is not human programming.

Do you mean for developing on Android devices?