The problem with the first video is that it speaks of one possibility as if it were fact, i.e. that the universe is infinite. It is entirely possible that the universe did begin at a single point and this still applies even if the whole universe is 20 times the size of the observable universe. It is unreasonable to speak of something we cannot actually measure or observe as if it were fact. The good thing about the video is the emphasis on the possibility of the infinite universe, because this is too often ignored and left out of explanations.
The point that the “big bang” is a terrible name for the theory nevertheless hits the nail on the head, because even if the universe is finite, the beginning is not a explosion into empty space but an expansion of space itself.
It occurs to me, it is interesting that the universe itself hides so much of itself – how convenient that we cannot even know whether the universe is finite or infinite. Somehow this seems an appropriate response to those who claim that God hides himself. LOL
As for the second video, the reason he gives for the many worlds interpretation being testable is the most ridiculous bogus reason I can imagine. For it to be testable you must have a procedure which can test it. Frankly, what I am getting from both of these videos is the the author likes the infinite universe and the many worlds interpretation. He would really like these to be true and thus he hopes they can be proven in some way that we currently do not know.