Whelp, one product I learned about at AMATYC that looked like it might be good to play with for STEM courses was Maple Learn. You could create live interactive web pages that draw on the Maple kernel, but use more intuitive language. You could share projects and lessons with others. Alas, when setting up an account it never sent me the confirmation email and when logging in I see this:

Maybe I’ll try again in a few months.