Maybe the Universe is a 4 spatial dimension Hypersphere

[Gibsense]

Misunderstanding of n-Spheres
While it's true that the "surface" of an nnn-sphere is an (n−1)(n-1)(n−1)-sphere, the post conflates the mathematical definition of hyperspheres with physical cosmology. A 3-sphere is a higher-dimensional construct with no direct physical analogy to our observable universe's 3D spatial structure.

Interesting opens the door for debate. I don't conflate it. I suggest that there is a whole different way of interpreting the reality of time and space and the 3 sphere is not a suggested analogy but a fact. A cross section of a 3 sphere is a 2 sphere and consequently the mathematics of a sphere are valid (used later). I need to quit to do other stuff right now but will be back as I disagree with much of your response.
I am not trying to describe conventional views here but to point out some alternative and real alternatives. see you later.