I thought spin down had something to do with pseudo-angular momentum of, like, electrons, but after Googling I see it definitely means spin down as the opposite

I thought spin down had something to do with pseudo-angular momentum of, like, electrons, but after Googling I see it definitely means spin down as the opposite of, like, spinning up an engine or a Docker container. Which is exactly what you said. Which is exactly why I didn’t try to guess what these things meant, because I had no idea. :)