It's Kotlin now. Kotlin has similar expressibility and extensibility, without Scala pitfalls. (Scala pitfalls that people didn't like included new versions having breaking changes, complexity, theoretical/academic features that weren't necessarily useful to consumer applications, and slow build times).
New versions don’t have breaking changes, they are just not binary compatible between major version upgrades which is true of many other languages as well.
Regarding complexity - scala has many features due to having a small number of clever primitives. Kotlin special cases many common cases, but imo that will be a more complex language down the line. I really don’t know what do you mean by academic features — one can make haskell libs with scala but they are libs, not language features. And build time-wise it is not that much slower than kotlin.
