I think Rust is not particularly FP because it encourages using loops instead of recursion and “let mut” is quite idiomatic in my understanding. Those two characteristics are more relevant than the type system. For example, Scheme and Clojure don’t have type classes but are clearly FP because recursion and immutability are idiomatic.

In Rust, even though it is true that .map, .fold, .filter, and .zip exist, first of all they also exist in Python, and second, they need to be sandwiched between .iter and .collect unless one is working with iterators which makes the code noisier and pushes the needle toward loops.

The influence of OCaml and Haskell is clear though, and it makes the language more pleasant to use.

I would phrase this as: adopted PL features pioneered by FP languages, but not in support of functional programming.

Like Java.

I think we come upon a phenomenan of cultural treatment of FP that makes it like AI - over time time some of the stuff invented initially invented and used in FP languages becomes adopted in mainstream languages (like eg closures, garbage collection, etc) and it gets gradually detached from the FP languages association and mainstream programmers aren't even aware of the FP origins.

(The AI analogy being: particular approaches start out being called AI and if it works out, ends up being called just normal programming technique when its adopted in mainstream - https://en.wikipedia.org/wiki/AI_effect).