I suggest you try a functional language before driving into Rust.
I've implemented a basic ML variant before, and maybe half a dozen different lisps. Rust is only BARELY functional. A C++ guy ought to know better!
Believe me, I'm not interested in Rust for Rust's sake. If there were a GNU implementation, I could see writing code generators for Rust a little less cumbersome than trying to target C or LLVM IR or Wasm.
Realistically, I see Zig winning the fight that Rust is trying to fight, and C++'s headaches being replaced with Rust's headaches.
There is no fight. There is made-up flame-war. Every war happen at HN and Reddit's Echochamber not at Real World.
Every languages has headaches. You won't find a perfect language ever.
You can't do serious Rust if you don't understand functional aspects.
I know C++, Haskell and Rust. Like many says Rust is a functional language disguised as imperative. There were case studies on Rust where a one with Haskell background more like to learn it faster than a one with C++ background.
The Rust book don't show you the functional parts at beginning to build your intuition but once you drive deeper you will realize what I meant.
https://ceronman.com/2020/09/17/is-rust-a-functional-languag...
Rust does have a lot of nice ideas borrowed (hehe) from functional programming, but it's far from being FP!
On a tangent: you're comment about learning a FP before learning Rust is great advice, but not for the reasons you initially intended perhaps. Learning FP in general is great, since it teaches you a different way of thinking from the "classical" way programmers think. So, it's great to learn FP for anyone, regardless of whether it's for Rust's sake (it will help a bit with reasoning about some Rust concepts and idioms, though), or not.
Graydon Hoare mentions Rust as linear ML in C++ clothing.
https://twitter.com/graydon_pub/status/1154476823557754880
I empathized the can't deny relationship between Rust and FP. It doesn't means Rust is a pure FP language. I always said same thing about C++ templates too.