Of course we want to get into the details. I can see there are many reasons why the earth maybe releasing more than it absorbs.
...and this is why I like posting here!
I did find a reference to heat loss from the Earth itself- 87 milliwatts per square meter. Core solidification is slower than I remembered, about 1cm/1k years.
https://phys.org/news/2020-12-earth.html
