Looking out into space is like looking back in time. Look 100 million light years away and you'll see what was happening over there 100 million years ago. Well, if you look far enough, you'll see what was happening 13.8 billion years ago. But at that point, it's just an opaque mass of radiation that we can't "see through" because this represents the birth of the universe, the big bang. What was happening 13.8 billion years ago, no matter which direction you look, was that the universe was being born. This is why it's a "ring".

This is called the observable universe and to be clear, I'm pretty sure current technology does not allow us to look that far. But this is what you would see.

As for what is "outside" it, our current understanding of physics can only extrapolate back to 1 planck time after the big bang. What was going on before that, in the moment of the big bang and any hypothetical "before", nobody can tell you. It's a singularity, it's where mathematical values reach infinity, and we don't really understand what happens when values reach infinity in real life. It's why people say we don't know what happens "inside" a black hole, it's the same problem.

Ultimately your question is one and the same as "what was before the big bang". My personal preferred idea is that space and time itself didn't exist before the big bang, therefore the very concept of "before" the big bang is nonsensical. So then what is "outside the universe", as far as I'm concerned it may well be a nothing beyond what you can even comprehend, a "place" in which space and time simply doesn't exist. Or it could be a gazillion pink elephants having a tea party. It's likely we will never know for sure.