You're thinking about rust the wrong way. When you want to write in that exploratory way you should use a language that supports it, like Python, Javascript, or Lisp. These are all memory–safe languages that trade run–time speed for developer productivity. You can implement new features in them extremely quickly, and later if performance becomes an issue you can reimplement in Rust with the benefit of already knowing what you are writing.

I’ve used Rust daily for the last 6 years; from writing compilers and WASM runtimes to writing smart contracts and SDKs… and the experience has been nothing short of amazing.

I’m not sure what you mean by a “casual setup,” but I find Cargo to be very easy to use. Granted, compilation can be pretty slow, but it’s a small price to pay for the runtime performance.

If by “faster feedback” you mean something that looks and feels like Python’s REPL, then I think you’re missing the point here. Rust is a compiled language.