Are you interested in the question of potential vs. actual infinity? That is, does physical reality have any actual infinities or are the infinities merely potential?
   IMO, infinities in mathematics are due to the nature of the modeling that we use. E.g. a line is infinitely divisible.
   The more physicists learn, the more they bump up against an innate granularity to reality. One way to view quantum effects is to postulate that space is quantized, which implies it is not infinitely divisible.
   In that case, infinity doesn't arise from a physical dimension. One implication is that the strange conclusions based on infinite countable sets being commensurate with their subsets apply only to the models of reality, not to reality itself.

   The Big Bang theory states that all the mass of the universe started at one point. Many scientists believe this.
   Einstein's Theory of Relativity states that there is no preferred coordinate system, but surely a coordinate system with the origin at the site of the Big Bang would be simpler.
   See Hall of Fame for a light-hearted how Einstein might view this.