I didn't have GPS in my car.
Because the cost of modifying the electronic box and updating the maps is very expensive, I found the following solution, I installed a GPS Garmin DriveSmart 51 LMT-S in the valet mode of my C7
Here are the pictures.
I put two plastic tips on the GPS.
The 2 tips slide freely on the GPS.
In each tips a foam piece made like a spring to repels the 2 tips.
The 2 end caps are retained by 2 copper wires (electrical wires)
The 2 wires allow the sliding of the 2 end caps.
The 2 copper wires are adjusted for the width of the valet mode + 1 cm.
A wooden plate placed flat in the valet mode allows the GPS to be positioned at the bottom.
An existing edge in the valet mode prevents it from moving forward.
The tips prevent the GPS from tipping over (foam pressure must be sufficient)
The GPS turns on with the contact.
The only problem noted was that you must validate the GPS when you start it, otherwise it switches to USB connection mode and you have to turn off the ignition (or unplug the GPS to restart it).
Since we don't use GPS every day, it's not a big deal.
The GPS offers several functions including one that interests me (the camera to put in front)
the GPS is perfectly readable and can be turned slightly towards the driver
The flap closes without any problem.
The GPS works perfectly with the flap open or closed.
In 1 year of use I have never had a GPS warm-up.
The GPS switches itself off when the ignition is switched off.
This solution is not the best but the big advantage is that
GPS costs 150€ and updating the maps is free for the entire life of the GPS.
And it works perfectly.
The funny thing is that the plastic tips were recovered on a slatted bed base.