The thing is that we can’t observe anything beyond the observable universe, so we don’t know what is there. However, it assumed that there is more of the same. Galaxies and space, possible infinitely more of it. Analyses of the Cosmic Microwave Background (CMB) indicate that the curvature of space is flat (possibly infinite). But within the error bars of the measurement the universe outside our observable part is at least 250 times larger than the observable part.
The farther away we look, the more the light is red shifted, which put requirements on our observing equipment how far we can see. The farther we look, the farther back in time we also see. The James Webb Telescope is an improvement in that respect, since it can in principle see in the infrared 13.6 billion years back in time.
The absolute edge that we can see is the CMB, which is the first visible light and corresponded to a black body radiation of 3000°K when it was emitted. It is now “stretched” to 2.7°K. The matter that emitted it was receding from us very close to the speed of light and from a gravity well, causing the redshift.
Then there is dark energy that speeds up distant matter going away from us, making it disappear over the observable edge. On the other hand, tomorrow we will see a bit more of the CMB light that has been moving in our direction from far away for one day longer (13.8 billion years plus one day).