Back country navigator and Gaia work pretty much the same. You download your maps over wi fi for the area of interest. I usually have three maps of the area; a topo, an aerial with topo and place markup and a NF map.
You don't need cell service to open your maps or to use your phone GPS. You can put the phone in airplane mode to save battery.
When you create a trip you can then add place markers and tracks as you travel. Any map that you load as you are associated with the trip will display the tracks and waypoints. Even if you load an entirely new map when you are back home.
The Google maps will probably work great if you have service but in many places there is none available. The two screenshots below are from a bunny walk a couple weeks ago. I live in a heavily populated metro Denver area with great cell service. The screenshots are from a place 30 minutes from home. NO cell service! That's pretty typical for my hunts.
So, if you are going to be going into those kind of places, either the Back country navigator or Gaia app will work.