The right hand controller of the X56 already has 5 analog axes (forward, lateral, twist, thumb-forward, thumb-lateral) and 18 buttons, and at the moment ArduSub and QGC only support using 4 control axes at once and 16 buttons, so the right hand controller is sufficient by itself for full control.
The benefits @Boko was discussing here was being able to use some functionality from the second controller by passing both controller inputs through an emulator to pretend it’s a single controller, which may be preferable to buying the controller pair and only being able to make use of one of them. If you’re happy to use a single controller then that should work fine once you configure the axes and button functionalities as desired.
PS4 and PS5 gamepads have limited support, and
Since those results are a bit spread between other kinds of controller, I’ve made a new surface-controller tag and gone through and added it to a few that seemed relevant.
For future improvements, last year we got changes made to the MAVLink MANUAL_CONTROL message to support additional buttons and control axes, but they’re yet to be implemented in the ArduSub firmware or QGroundControl. Progress on that is in the issues linked to at the end of that one.