GPS turns off during guidance
It looks like the setting marked with a red circle in the picture below has no effect. My Samsung S8+ turns off the GPS when the screen is turned off. I can see this because when the screen is turned on, the position is still where it was and it takes some seconds to update the position.
Well, it is some battery optimization in Android, you could say.
I don't think so. When I turn on live tracking in Locus Map, the GPS is always on as it should be so it seems that Locus Map can control this, but not without live tracking on.