You can’t trust thermostat ratings

IMHO...
There must be a time element to heat transfer.

Move your finger through a candle flame.

Move it fast no burn (less heat transfer from the flame to my finger)

Move it slowly and I get burned (more heat transfer to my finger)

Or am I missing something here?
Then use a smaller radiator or 6 blade water pump.
Some of you are on autopilot or something. Complete the thought. Lol