i have as much interest in science and tech as anyone else, but sometimes these cosmological ideas or whatever seem to be just speculation and have no empirical evidence to support them.
The first half of the video doesn't have much bearing on the second half. The first half presents any 4th dimension as having the same scale as the other 3, but the 2nd half does not. Which brings into question why bother mentioning the first half except as some sort of contrived mind game. Atleast there is some evidence for an expansionary universe.