In this article you will find the option to change your aircraft state once it loads into the simulator.
In the Tablet, you will need to go to the Fenix App > Select Panel States on the bottom bar > Cold and Dark (or whichever panel state you fancy)> Set as Default > Activate.
On aircraft load in, it will still load in fully started. Please give the simulator 20-30 seconds to fully load in and apply your default panel state.
The aircraft will always load in the ready state regardless of the saved state when you load in on a runway.