These things are to be avoided by every means, eradicated by fire or iron or any other means: disease from the body, ignorance from the soul, luxury from the belly, faction from the city, division from the household, excess from everything.
You talking about the torture porn document which looks like it was written explicitly to get the goat of doomscroll addicts, complete with scary quotes on all black pages, rather than soberly conveying important information?
"Heat" isn't a physical thing of it's own. Electromagnetic radiation transfers "heat" by adding energy to electrons which it impacts, bumping them up to higher energy orbits.
I suppose I'm confused by your "that's not the sun" statement.