After cruising the comments and reading your post twice I propose the following because I’m that asshole today:

Go by layer.

Okay, so, assload insta-death ballpark Celsius in the center, okay fine. Maybe median this one. Then, consider some other identifiable layer(s) between there & surface, with some more eyeballing. THEN, for good measure, as many surface temps you can get for sea/land/air if you have chosen the range to include atmosphere.

Report back. I’m half asleep and haven’t checked my work. Also. I only ever need half a reason to suggest implementing excel to assist in your calculations 😂 I’m so sorry