To keep your phone cool while gaming, ensure good ventilation by removing any bulky cases and playing in a cool environment. I avoid using big rubber cases and metal cases.

Lower the screen brightness and disable unnecessary background apps to reduce processor load.

Opt for power-saving or low-performance game settings to minimize heat generation. It helps outdoors when you have no cooling headroom for the processor. 

Taking regular breaks can also prevent overheating, allowing the device to cool down. I avoid playing genshin more than 1 hour in a single go without Letting my Iqoo 12 cool down

Additionally, consider using an external cooling fan or placing the phone on a cool surface to help dissipate heat effectively. Fans with metal backs are best at cooling phones.

When I play genshin impact on my Iqoo 12. I use battery saver mode when I'm outdoors and when the battery is low I let the phone cool down before turning on charging so I don't Damage battery Health

Happy Gaming