Doorknob Wall Guard

In one of my bathrooms, I noticed a poorly filled/refilled area where there was at one point a door guard for the door knob. Rather than mucking up the wall, I used the dice-shape in Tinkercad and made a 4"x4" (102mmx-102mm) by 10 mm square disk.
I have some industrial double-sided tape, but I assume regular double-side will work as well.