In a recent interview Sony's mechanical design chief responsible for the PS5's cooling system revealed an interesting bit about the console. It turns out it will offer per-game fan control, using data collected from AMD's APU on board and will eventually improve the cooling performance of the console over time.
As games go out and people start playing them, the APU will start collecting data so no "one size fits all" type of fan curve will be used here. There are multiple temperature sensors placed all around the board to help collect the data.
Moreover, Sony's engineers designed a transparent case and pumped smoke from dry ice into the chassis during the testing stage to see how the cooling system performs in real-time and also track the airflow.
Source (in Japanese)