[krapp]

>Namely, can run on Windows without it being a ridiculous exercise in hackery, comes with a robust set of libraries that I can end up using it to solve actual problems I might eventually receive money for solving, and has enough study material to lead me through it.

Racket seems to tick all of your boxes, IMO. Also maybe Clojure. I've gotten both to work without much problem on Windows, both have an ecosystem and plenty of tutorials.