You can use a command line switch to turn the backlight on and off.
I’m just getting started with this. Usli is not difficult - show the code.
Firstly Google and find the code to turn the screen on and off. Then make a command line switch as per the docs. Then use an automation triggered by your motion sensor.
with the code for switching the screen the problem is - I can not find it.
my mistake, you don’t even have to google, it is in this thread.