Turn off everything possible on inactivity

I am building an AR app with Unity for an exhbition. The app runs in Guided Access. I am checking the inactivity of the user, and after a certain time, I want to turn off everything possible, to optimize the battery usage. Currently - even if the screen goes dark - the battery is drained quickly and the device is very hot.

Can you give some advice how to achieve this?

Is there an option like, turning off the Unity process when inactivity is detected?

If you use AR Foundation, place SceneUtility and SceneUtilitySetup scripts in the project. After a certain time (which you use) go to the “menu” scene of your app (without AR stuff).