that's PID control, it's a tad advanced and most likely not necesary to start by the most complicated fan control option
it's a control method used a lot on industrial machines. Nerdy users may want to experiment with that sometimes, but it's rare anyone uses it.
https://en.wikipedia.org/wiki/Proportion…tive_controller
You define those 3 factors so the systems responds to load without like brutal fan accelerations, or decelerating too soon after load, causing oscillations etc.