earth's internal heat from the core and mantle contributes about 0.03% to the planet's total surface energy budget, dwarfed by solar input.
wikipedia
https://en.wikipedia.org/wiki/earth's_internal_heat_budget
quora
https://www.quora.com/what-percentage-of-earths-heat-comes-from-earths-core-as-opposed-to-the-sun
What if the earth wasn't a globe but a level plane with a dome overhead, would the assumptions still be true?
in a flat earth model with a dome, the whole concept of an internal core heat budget falls apart—there's no core in that pseudoscience setup, so assumptions grounded in real geology and solar physics wouldn't apply at all.
wikipedia
