I think Hubble tension could fit into this if the sphere/balloon is also expanding/growing/stretching away from the centre. In this case it would be the fabric of space being stretched though. So not sure how that’d fit into this model exactly.

There was also a scishow or spacetime video about how gravity can be seen as an emergent property of "time / causality is slower the nearer the gravity well", and that is how gravity works. To truly understand it you have to understand the math and how to solve it, afaik our explanations are all rather imaginary. So you could probably interpret the math to mean that this "spacetime bulging" is the result of a spinning universe.

Yeah. I think so too.

The bigger question is: Where is the rest of the matter that spins in the other direction? It should have perfectly canceld each other out! (like matter and antimatter also didn't)

Dunno tbh. Maybe it’s double-sided and it’s on the other side of the balloon/membrane?

(And for some reason my brain associates this spinning sphere analogy with gravastars 🤔)