the universe expands from all points, everything gets further away from everthing else, its the 3d equivalent of the 2d surface of a ballon being inflated. Draw a face on a balloon then blow it up and the features expand away from each other. Because of this the big bang occurred not just in the distant “edge” of space but everywhere in the universe is the point of the big bang. Physicists just try to observe the BB at great distances as the further you look the more back in time it is, nothing to do with the big bang being far away.
The surface of the balloon theory like the mobius strip is an aid to understanding the no edge theory of 3d space too, as this is beyond human comprehesion unfortunately, well mine anyway.