There are more possible inputs than any HOTAS setup can reasonably be expected to handle by mapping a single input per button, requiring for maximum comfort to setup button combinations. That works well, with the only drawback that I can only use a single device’s buttons.
I suggest that you implement shifting across devices, such that I can press a button on my throttle which can be combined with a button from my joystick to do something.
I understand this is available from third-party tools, but having support directly from the game is always a better option.