One of the main problem with the standard model is connected to the assumption that space-time is expanding and the expansion of space-time is leading the matter of the universe to expand. The analogy is like blowing up a balloon and watching the dots on the surface expand in all directions. The expansion of space-time is attributed to dark energy, which is like the air that fills the balloon.
The problem is they have not been able to make dark energy in the lab. We will need some dark energy to first prove that dark energy is real, and then we can use it to make space-time expand in the lab to prove the expansion theory. But since dark energy has not been actualized in the lab, the current theory of expansion has no lab proof. I could just as well say fairy dust is the air that blows up the universe balloon. I also cannot make fairy dust appear in the lab to demonstrate. Both theories are in the same science boat and none of them should be carved into stone.
What I can prove is, I can make space-time expand in the lab by moving mass apart. General Relativity makes change in space-time a function of mass and distance. This is actually a more solid theory, since this already has lab proof; saves money and time. Yet, the standard model prefers the one with no lab proof and a big budget. To me that means the problem is still open for change, in spite of company politics.
A better universe creation theory, that can let matter/mass lead a provable expansion of space-time, has the primordial atom or the singularity, first divide like a mother cell, into umpteen daughter cells, before the Big Bang. We start off with billions of cells; embryo universe superstructure, each destined to become a galaxy.
When the BB t=0 instant occurs, we get billions of smaller bangs, all at the same time; summation of the BB. The matter/energy expands, creating powerful lead energy waves, coming to each other, from all directions. This pressure puts limits of individual galaxy matter expansion, allowing blackholes and even stars to form quite early. The universe also expands relative to the galaxies.
The main difference between this theory and the standard model is the standard model, by atomizing everything all at once; BB, takes more startup energy and generates more early entropy, which cools the universe quickly. The cell model does not need as much start up energy, all at once, but rather each split can occur with a continuous trickle of zero point energy.
This split into cells is not based on matter, but more like black holes splitting, with space-time staying very tight. The extreme time dilation takes advantage of near infinite time to gather zero point energy. At the last cell division, there is a shift from a huge cluster of black holes into a huge cluster of white holes, causing space-time to appear and expand in all directions, The pressure of the energy waves, from all directions helps with galaxy matter containment and creates a universal expansion relative to the galaxies. Central galaxy black holes can also reform. The simultaneity should show up as a uniform cosmic background energy.