Good thing you managed to get it going!
First of all you need to make sure that the controller is recognized as a joystick in the operating system. Windows and MacOS uses different input systems, therefore it is not guaranteed that a controller that works fine on Windows also works fine on MacOS.
During calibration in Freerider, keep an eye on the little circles above the OK button. If you can move some of the little circles smoothly up and down using your sticks it is possible that you will able to use it to fly. (The circles shows exactly what is coming though the input manager).
If you still can't get it recognized correctly I would suggest going to a forum dedicated to the controller in question, or asking the manufacturer of the controller, perhaps they have some answers to how to get it recognized as a joystick in MacOS.