Switch mixer in air

Hello, it’s been a while I’m working on a project and I really struggle finding a solution.

The idea is to have a standard quad-x drone flying, able to switch to a boat mode when landing on water.
The boat mode is pretty simple : 2 of the motors used to lift the drone are rotating 90 degrees and are used to propulse the boat.
As I have no problems making the boat mode, I’m facing the following problem :

My boat and my Quad-x both use the same motors, but with different mixers, so I need to be able to switch my mixer during the flight, which doesn’t seem possible ( at least for the few I know on PX4 ).

I tried to take example on the VTOL configuration, but actually the VTOL uses different outputs, so it is not facing this problem at all.

Does anyone have any idea about how to implement this ? Thank you in advance,