Nice article. My one problem with it is one that I find in almost every article about Kotlin. It implicitly attributes so much to Kotlin that didn't originate with Kotlin. I would argue that 95% of Kotlin is watered down Scala meant to be more appealing to Java developers. Five of your six bullets are things that Kotlin took directly from Scala, but you only mention Scala for the last one.

Scala 2 avoided explicit enum declarations with the idea that they could be modeled with other language features. That didn't work as had been hoped so Scala 3 has put them in, but I'm pretty sure most of the concepts for enums in both Kotlin and Scala come from Java and are just adapted to the more concise syntax for classes/constructors that Scala introduced.