For anyone showing up later without gun knowledge to see why the first test is fatally flawed... Bird shot loses its penetrative properties as it spreads. This has to do with multiple rounds impacting an area of material. Seeing this replicated in the second video would have been very helpful but the content creators dismiss it because it's pretty well known birdshot isn't going through walls the same way and they wanted a funny video. (At one point they fire an M1 Garand at their walls)

What a lot of people miss about self defense is that you should also be into reloading. (It makes practice so much cheaper too) If you can reload your own rounds you can find the lowest load of powder that will cycle the bolt on your weapon. Less powder equals less penetration, but seeing as a 22 LR is lethal at home defense ranges (that comically tiny bullet that kids shoot) it will work. And you've got to practice anyways.