Ahh, but you appear to be seeking a reality where you might, in theory, be outside the universe and look back at it, as a distant observer. Much as we can observe a mythical flatland from a third dimension. Perhaps THAT notion is not rooted in reality.
And, while I agree that flatland does not represent reality, Abbott's work provides a tool for the mind, to help it see possibilities outside of its ability to experience examples.
If mathematical theories can not be supported with physical examples, then they should be seriously questioned.
In OUR reality, 2 + 2 = 4 and it can be easily demonstrated by combining 4 physical objects.