Much is misconception. As Steve said, cpu could be 90°C, coolant temp 30. Doesn't actually stay that way for long, usually ending up closer to 45ish°C.
Too many think that just because the cpu is high, the rad will be blowing hot air. It shouldn't. With liquids, they absorb the wattage from the cpu. Not the temp. The temp the cpu sees is what's being used under load after the resultant wattage is removed. You aren't going to get a 9900k/10900k at max oc/max loads to run at 50°C even with 4x 480mm rads. Doesn't work that way.
So if you have a 150w OC on the cpu, the coolant will absorb that 150w. That's not enough wattage to boil water with any speed, or really change the coolant temp even 1°C . The coolant is shunted into the rad far too fast for that to happen, where the fins which are colder than the coolant then absorb that wattage, or most of it. It's that excess wattage that'll slowly add up to a constant amount in the loop, and warm up the coolant.
You aren't blowing 70°C air into the case. You are blowing 100-150w charged air from a 30°C coolant. The 'low' setting on a hairdryer is @ 450-500w, the high setting being 1200-1500w. Just for comparison.
If an AIO is sized correctly for the load, the air entering from a front mounted AIO should only be a few °C above the ambient outside air. That's it.
Numbers used for example purposes.