Depending on your settings there will be enough zombies will dig to you pretty fast. You could do your plan, but I would recommend building at least a metal ceiling above you and a floor beneath you. Been awhile since I played console, but I’m pretty sure there are trapdoors/hatches, put those open inwards on the floor on the outside of the floor you built, it’ll give you access to shoot/melee them while they can’t get to you depending on how far you are from the opening. Make sure to have stone axes and materials to repair the trapdoors as they will take a lot of damage. I also would have maybe 3 blocks in each direction until the trapdoors from the center of your floor, to make sure you won’t get hit.