[Multimodal]

Do you mean how can you have all the electronics stay off? I don't think that's possible and it's by design that the car is responsive to your presence. You have to trust that the vehicle is smart enough to do its own power management. This is the way of the future for vehicles - my neighbor's Tesla X, for example, keeps its taillights on all the time while charging, which always makes me think he's left his car on in his garage.

When you exit the vehicle and walk away (or, if you've disabled Comfort Access for some reason, press the lock button) it will shut down the engine and all electronics.

I don't even bother to press the start/stop button to turn the engine off. With auto start/stop I trust that it will go from Ready to Off when I lock it.