Who I have the same questioned this topic

How to I blank my screen to save battery power while Google maps is running and NOT have it drop the GPS signal(and thus exit navigation/maps)? This worked fine in all previous Android versions. I was in the "optimized" battery option by default. I tried "medium with "restrict background apps from using WIFI and Mobile data" turned off. Both options still kill the GPS signal connection when the screen is turned off (& thus the phone is locked).