I don't think Scala is a good comparison. Due to the fact that it has a large surface area and there is a lot of magic in places, it's harder to learn than Kotlin. Also, Scala suffers from C++ syndrome, where a team of developers that all nominally know the same language can actually know somewhat incompatible subsets of it.

I think the Typescript/Javascript comparison is more apt, and at this point I'm pretty sure that Typescript will win.