universe is a relative word, and typically treats us at being at the center (which in the whole of reality is somewhat unlikely). So it only describes that part of reality observable by us. 8,5 bn ly refers to roughly half distance to all of the observable events in that observable reality at the time these events occured. Since 3D space presumably expands, it would now take much more time for any event in our observable "universe" to reach from one end of the observation limit to the other...

by the way - if you want to go down further that rabbit hole a good place to start is to search for "levels of multiverse"