I did this with the thermal sensor. 2x noctua 5V fans and an old phone USB power adapter. Works really well though the fan runs at a set speed.

If you are looking for a proper solution then checkout AC infinity, that'll give you everything you need I expect.

Otherwise you're looking at a self build option of a fan controller and an appropriate power supply, I just used some relatively quiet highish airflow fans in my rack run at a pretty consistent speed using a basic fan controller I 3D printed a bracket for, I might turn them up a bit in the summer if the temps are showing high..