there is already a setting for this by default, its the Del key (on pc, no idea if its a default key for controllers) you can map that to a button but i dont know if it will map to an axis like rudder pedals (buttons and axis’ act differently) since ive never tried it
i have ‘Brakes’ mapped to my trigger button (hotas) by default and then i have my differential brakes on my pedals, its Totally possible to use both, in fact i would think that the differential brakes are secondarly since not everyone would even have that kind of controller
looking it up the brakes are set to the Del key by default, that will apply both brakes 100% is the only issue (you learn to ‘bump’ them to slow gradually - or use the pedals :P)