Nothing, except silver, can match copper's heat conductivity, and it it is totally safe as having been used in cookware for many many decades.
I have some copper cookware, but the food isn’t in contact with copper (copper is lined with other « safer » metals to avoid that, like Vapman) and while the copper outer part of the casserole is in contact with a blue flame, it rarely pass 100*C as there are many ways of dissipation (its huge radiating mass and the food inside, boiling and evaporating).
in your device copper should reach higher temps, so maybe it is not the same-same
I also use copper in the garden, to kill fungus and other micro organisms and protect my veggies, it is not safe to inhale that
again, different applications different risks…
also: pyrolisis or charring tastes really awful IMO