Kotlin is like Scala (more ergonomic and with immutable collections in the standard library), but without implicits and with Java's weaker type system. It also has more compilation targets than Java (js, llvm, jvm).

Java is already taking hints from Scala and quickly adding Scala inspired features, which is making it similar to Kotlin. I think unless Kotlin innovates and does something not already in Scala, it will likely run into the issue of being too similar to Java ~20.