The event horizon is not a physical surface. It is just the distance at which escape velocity exceeds the speed of light any closer to whatever is inside. That does not mean that an object could not penetrate the event horizon, if the radius is big enough that it does not create tidal forces that tear the object apart. From far outside, General Relativity solutions indicate that it appears that time slows to a stop for objects that approach and reach the event horizon. But, from the object approaching the event horizon, time does not appear to be slowing down, but distances appear to be altered, compared to a non-accelerating observer who is well outside the EH.
So, what happens inside the EH? What would it look like to an observer, who, let's say, fell through an event horizon that is 13.8 billion light years in radius (as estimated from inside the EH)? I read an article (that I can't find right now) that claimed such an observer in such a situation would see what appears to be an expanding universe. But that article did not present or describe the method for solving the General Relativity equations necessary to reach that conclusion. So, it just leaves me wondering.