Generally speaking, if a controller can be recognized as a joystick by the operating system there's a good chance that it can be used with FPV Freerider.
However, I have heard reports from many people that the betafpv literadio2 does not support joystick emulation on Android. (I do believe it works in Windows though).
Since it is not recognized correctly by the operating system there is nothing I can do about it unfortunately.