Julia Child did some 400° cooking, for a science-oriented TV series called “The Ring of Truth”: https://www.youtube.com/watch?v=WQ3mjb9BSaU&t=850s
Later in the episode, she got to cook a diamond to amorphous carbon. “I’ll remember that recipe – one carat diamond, two and a half hours, three thousand degrees”: https://www.youtube.com/watch?v=WQ3mjb9BSaU&t=1458s
They’re just following John Green’s policy on electricians and witches: “If you don’t know how to do something well, hire someone who does. My policy is that I don’t change the wiring in my own house, and I don’t hex my own enemies.” (https://www.youtube.com/shorts/mxdwS3f209E)