Black body radiation was my thought as well. It may not be the average including the inner layers, but it’s the average at the crust. About -1°F according to Wikipedia.

To add to this, is probably hard because the composition of the interior of the earth is a lot of guesswork. We can only directly observe how much heat is coming out of it.

https://en.m.wikipedia.org/wiki/Thermal_history_of_Earth

If you take out the employer-side taxes and cost of benefits, maybe. A fair number of their employees must be software engineers, and that much compensation isn’t unreasonable for expert software engineers.