''outside the universe is that it is one'' What does that mean, though? That's an illogical thing to say. One what, I have one bottle, but many things can fit inside it, just because it's one it doesn't mean inside it only one thing can exist just like ''outside the universe''. How do you know only one thing exists outside of our universe? That makes 0 sense. You are just making shit up, literally.
The idea of making the word "outside" to be made up of several letters of the alphabet, is an idea of mankind. But it is still one word.
When you try to confuse the idea of one outside by using all kinds of meaningless blabber, you are actually showing that you understand the truth, but simply are against the truth.
Right...... So how do you know there is only 1 god outside, again?
Well, get out there and figure out how to relate to outside-the-universe. As it is, God is outside the universe. Outside the universe is one. God is one. Easy logic. Easier than pie.