I would leave GPS enabled. It's not only Find My Mobile / Find My Device apps that can use GPS. Gmail, Google Maps & a number of other apps can use GPS to locate a lost cell phone.
At one point, without Cell service, WiFi, Bluetooth & No GPS, no there's no way to locate the device. Only thing left, would be the last known location.
Hi, In order to use Find My Mobile, these conditions must be met:
•The phone must be turned on.
•The device must be connected to a stable network connection.
•A Samsung account must be added to the device.
•Remote controls must be enabled on the device. This feature will be turned on by default when you add a Samsung account to the device.
•Remote unlock must be activated in order to use the Find My Mobile unlock feature