There's multiple factors that change airflow characteristics. One of the best airflow cases is the fractal design Meshify C. It has 3x intakes and a single 120mm exhaust. What it also has is a closed top, no fan vent unless you remove the silencer cover.
The why is easy, if you understand how a fan works. The blades are pitched, when it travels through airspace, it creates a low pressure zone right behind it, the byproduct being the air pushed out the back of the fan. Faster the blade moves, stronger the low pressure area. But, air is air, and the further away from source you get, weaker it is, so the strongest draw of low pressure is closest to the fan.
Which is almost always parked at rear exhaust and almost all cases nowadays have a top fan vent directly above it. Guess where the rear exhaust is going to get a good chunk of its air from. Not the case, but that fan vent. So the rear exhaust is only half as effective as it could be. Which leaves a lot of heat in the case.
It's impossible to cool something lower than ambient temps by mechanical means. And an aircooler is most definitely mechanical. Not chemical. As your case gets warmer, the ambient air of the cooler gets warmer air, not outside temps, but inside temps, making the cooler less efficient. Cpu gets warmer under loads.
Air FLOW is what's important, plenty in, plenty out, in a nice straight stream. If not using top fans, cover the holes, force the rear exhaust to pull out case air, and it's heat, to be resupplied by cooler outside air from the intakes.
Just drop a book on top, temporarily cover any holes, see how that changes cpu/gpu temps overall, remove obstructions like unused hdd cages from intake area, force the pc to do what you want, not what it wants to do.