The Go app runs in the background on my samsung s6 even when I've restarted my phone and have not used the app.
It drains the battery and uses data even when I'm not using, nor have used the app.
I thik DJI needs to fix this. There is no reason for that app to run in the background after the phone has been restarted.
I've gotten to the point where I uninstall the app if I'm not going to fly for a while.
For what it's worth, the Litchi app does this too.

You are not alone! S. DJI GO - Android - App always on!, DJI Go - Android version and high data/battery usage