To me, Scala's issue is identity crisis, not complexity. Some of the community wanted to pretend it is Haskell, and others wanted a better version of Java. But if you want a JVM functional language, why not Clojure? If you want a better Java, why not Kotlin (or update Java). Scala is squeezed by more consistent alternatives on all sides.

I don't think that Rust has the same issue: it has a clear (albeit potentially complex) vision of what it is trying to do, which is distinct from C and more consistent than C++.

I think "better Haskell on JVM" (in contrast to "worse Haskell") is a good identity for Scala to have. (Please note that this is an intentional hyperbole.)

Of course, there are areas where Haskell is stronger than Scala (hint: modularity, crucial for good Software Engineering, is not one of them). And Scala has its own way of doing things, so just imitating Haskell won't work well.

Examples of this "better Haskell" are https://typelevel.org/cats-effect/ and https://zio.dev/ .

All together, Scala may be a better choice for you if you want to do Pure Functional Programming. And is definitely less risky (runs on JVM, Java libraries interop, IntelliJ, easy debugging, etc...).

None of the other languages you mentioned are viable in this sense (if also you want a powerful type system, which rules out Clojure).

I agree that Rust's identity is pretty clear: a modern language for use cases where only C or C++ could have been used before.