One thing that might help is knowing that the crust is very thin, 1% of the Earth’s mass. The core is 15% and the Mantle is 84%. But we don’t have to be too exact — the earth’s mantle isn’t one temperature
The Mantle ranges from 1000°C near the crust and 3700°C near the mantle. The core is starts there and gets up to 6000°C.
So, just a simple formula weighted by mass might be:
.84*((3700°C+1000°C)/2) + .15*((3700°C+6000°C)/2)
Which equals 2701.5°C. That answer might be fine for a Lemmy but an academic paper would have major error bars.
I also asked ChatGPT and Bard, out of curiosity. ChatGPT was more conservative and told me it’s hard to get anything besides a rough estimate. Bard warned about all that too but then said probably between 3000°C and 4000°C.
So, I’d say about 3000°C. My quick and dirty little formula could easily be +/- 1000°C and fall in Bard’s range.