I think the «best practices» found in Java enterprise has meant that a lot of people think all Java has to look like that.

High performance Java is awesome and can be competitive with C++ and Rust for non trivial systems, thanks to much better development cycle, debugging and high quality libraries.

Most the benefits is the JVM, so Kotlin has those too, but I don’t feel Kotlin is enough of an improvement to warrant the downsides (at least for me). But both Kotlin, Scala and Clojure are great for the Java ecosystem.