Hole Cutout in a 3d Object (Wall)

I'm trying to make a "Hole in the wall" game for my semester project. For which I need different cutouts in the wall for player to pass through. But unable to do so in unity.

I tried using pro Builder's Boolean but it only make cutout with refrence to only probuiler's own mesh objects.

Someone recommended to use blender's Boolean modifier, but the problem is it can cutout holes with simple meshes, but when I try to use an avatar or character as cutout reference it doesn't do so.
Can someone please guide me how to achieve these cutouts in a wall in unity or blender or maybe in other 3d software.
Thanks for the help.