itch.io

A little late, but I doubt you’ll get a Steam key as the product itself has been delisted from the Steam store.

https://store.steampowered.com/app/953300/ART_SQOOL/

Notice: ART SQOOL is no longer available on the Steam store.

Genuinely one of the better puzzle games I've played in my life. Inventive, fun, and ridiculously well polished.