I kinda ran out of steam building my own calculator, which is here: https://recomputer.io/ . I haven't seen insect before, and it looks great! Especially given the landscape which I documented in the github readme: https://github.com/xixixao/recomputer
What a coincidence. I just linked Insect in another comment thread a couple hours after this post. I thought you saw my comment and made a post for it. Nope. Turns out you're the OG.
Insect is my go-to calculator when I'm not in Emacs. Excellent program. Although I'm not a fan of NPM being its method of local installation.