Thats my point— there is no “sides of the universe”whats on the other side of the “side”? or if we are in a bubble- then whats on the outside of the bubble?- the human mind cant understand a no beginning and no end of space— its forever and ever with no end never..
If you think about it, the concept isn’t really that hard. For instance, what is “the other side” of a common Möbius strip? At first you think “it is the other side of the strip”, but the truth is that the strip has only one side.
The universe is like a 3 dimensional Möbius strip. If you go far enough on an exactly straight line in any direction, you will end up where you started.