I don't know about Udemy or Skillshare, but I gave up on Coursera a long time ago because almost everything on there seems to be of a "X for non-X-majors" varie

I don't know about Udemy or Skillshare, but I gave up on Coursera a long time ago because almost everything on there seems to be of a "X for non-X-majors" variety. They tend assume no prerequisites and are generally super watered down.