How to force disarm, even when in air?

Murphys law states that crashes are unavoidable.
I usually disarm my drones before they impact the ground to prevent further damage and ESCs burning up (coming from Betaflight, this is possible).
PX4 however will keep the props spinning because “Disarming denied! Not landed”
I know there is a kill switch, but I don’t want to use that for two reasons:
1 my muscle memory is tied to the disarm switch
2 I want the control surfaces to still function (as in prearmed mode active)

How can I achieve this?

You have to use the kill switch, or send a MAVLink command with the force parameter set, or otherwise you would have to change the code.

What is the key combination for the kill switch in QGC

I didn’t know there is one?

OK, so the only way to assign a kill switch through QGC is by assigning it to one of the flight mode channels!!