OK, let’s look at three explanations of gravity:

General Relativity: there is warped space that “follows” objects around where ever they go, and the warp is proportional to the mass of the object, and diminishes in magnitude as the warp extends out into space away from the object.

Vacuum energy density; the vacuum energy is proportional to the movement and mass of objects in space. This concept works best in a universe filled infinitely with mass and energy, where the vacuum energy density is in balance with the matter/energy in the universe, i.e. cosmologically “flat” and infinite in size and content. In a finite universe, it means that a flat or open universe will expand forever and complete entropy will result. In a closed universe it means that the entire universe will collapse.

When an object moves through space, vacuum energy results in the void it leaves behind. A big crunch would be surrounded by a huge amount of vacuum energy in the arena from which the matter/energy that formed the big crunch was attracted from. If the big crunch results in a big bang, the expanding bang universe would expand and even accelerate into the relative void of the arena due to the bang itself, and due to the vacuum energy in the arena.

Neutrino pressure: Give me a quick description of how this would work in comparison.