Here’s the thing:
While you can zoom out and see all three zones of this background, but this black bar on the top and bottom of the screen is kind of obnoxious. In addition, the actual background and characters in it are very small. If you want to do this, you’ll need to zoom on the middle of two or three zones to a % less than 100 like I said before. Just be wary that characters that would usually sit at tables or stand towards the front of the screen will have their feet in the area of the black bar.
This is why I don’t really recommend this. For the reader on a phone, they have to look at tiny characters on the middle of the screen which may disinterest them in the story. Learning how to work with zones and zooms will help to add the dynamics while having less risk of taking them away.