the screen doesn't contain anything but a display controller. The HMI controls what gets shown.
But there is no guarantee that if you have Gen5Diy hack up an HMI that works in your car, that it will be able to control the ambient lighting because your ambient lighting appears have a module that is programmed to listen for the Drive mode either thru ODB2 communication or one of the GMLAN type busses. It may not be programmed to listen for the commands that the app would submit that are independent of the drive mode.
And i dont think gen5Diy has anything that reprograms the ambient lighting controller. But maybe they'd be willing to help anyway.
You might need to also buy a US ambient lighting controller to utilize the hacked HMI from gen5diy. These go for around 90 bucks used in the US.