I enjoyed reading your article because I have experienced much of what you talk about.

In my case, I develop a prototype or pieces of one using Mathematica (also known as Wolfram language). Mathematica notebooks, like Jupyter notebooks, Mathematica notebooks is a REPL environment with lots of visualization tools and libraries and a lot of fun. Once satisfied, I switch to JavaScript (I write web applications) and the Jest testing framework to follow a TDD approach. I also switch back and forth between those environments as needed.