02c. Fan
The Raspberry Pi Active Cooler for Raspberry Pi 5 is cheap, easy to install and maybe it brings best performance for your Raspberry Pi 5.
Fans are usually designed for 5V power supply. A PWN-controlled fan is recommended. This can then be configured in the config menu. Connect the fan to pin 2 or 4 (5V), to one of the ground pins and - if using a pwm fan - to the selected pin. Default for pwm is GPIO 18 (pin 12).
Image 3: From https://www.raspberrypi.com/documentation/computers/os.html under a Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA) licence.
No liability is assumed for any damage caused by errors (including grossly negligent) in these instructions.