The solder issue came about BECAUSE of poor cooling. The new solder just wasn't tolerant of those temperatures.
It was a series of smaller design flaws which compounded into a giant stuff up.
Boards warping, shit cooling, hot components... It was never going to end well.
Solder comes before temperature stress tests, not after. Otherwise, the non defective units would have had a different design. OTOH, other components might have had poor heat tolerance and also needed replacing.
Simply put, the issue wasn't cooling the console so much as making sure it would work at that temperature. Cooling problems imply fan failure or mechanical issues slowing heat exchange.