> I don't think it's really possible to seriously consider Haskell as somehow less "dizzyingly complex" than rust unless you're already a math postgrad.

This seems clearly false to me. Haskell has a higher abstraction ceiling than Rust, but unless you want to contribute to a particularly heavyweight library (`lens` comes to mind) you can get by just fine without going anywhere near it. In practice, most code in both languages maxes out at or below the mathematical sophistication of an introductory algebra class.