Space or outer space isn’t a term commonly used in cosmology which is the field of study of the chronology and evolution of the universe.

And in this context it makes perfect sense within 1b light years we can observe the universe as it is more or less in its current state, so looking at something 100 light years away or 1b isn’t that different. Once you go past that line you begin to go further and further in time so different stages within the evolution of the universe take precedence over local phenomena.

It doesn’t indicate that there are other universes out there just due to the speed of light what we can observe can be drastically different than what is around us as well as what is actually going anywhere else at the current age of the universe.