I may have read your post the wrong way, but it seems that they did provide a way? The specifications on the product page [0] mentions it got speed control with

I may have read your post the wrong way, but it seems that they did provide a way? The specifications on the product page [0] mentions it got speed control with PWM, I figured up to the Intel specs, to be able to use an off-the-shelf fan. So if anything you should be able to connect the PWM pin of your Noctua fan to one of the GPIO pins, and use their software to specify the PIN number of your PWM output. What seems more complex is to get the input from the fan about the actual speed, which would be useful to detect that the fan is blocked and is not doing the job you ask it to do. [0]: https://www.raspberrypi.org/products/raspberry-pi-4-case-fan/?resellerType=home https://www.raspberrypi.org/products/raspberry-pi-4-case-fan...