Flight controllers are for automation, gps, gyros and are used in quads to control cameras, video, motors etc.
I would still buy some basic servos, 5-9g cheap ones, then see if they work.
Receivers that only need to talk to a flight controller use different signals to those that talk to servos, a servo is basically a motor. PWM is Pulse Width Modulation, a signal sent to the servo, which the flight controller wouldn’t usually read. Any receiver with servo plugs will be some form of PWM.