They’re disabled by default. I suppose to maximize thermal cooling and battery life? to utilise all 4, you need the governor for it (already included with the stock OS image) but hey, sounds like you need the gearbox GUI version:
The link above is a step up from clockworkpi’s terminal-only gearbox and should’ve been included in future image updates of the OS from now on really.
While you’re at it, tweak the fan speed too:
lemme just say that I apologize on behalf of the community here that the information regarding the device is all over the place. A little bit of search could go a long way, so I hope the two linked above could point you in the right direction. Do stay around and have fun with your devterm!