One complication is that since the universe is homogenous and infinite, there’s a boundary that is expanding away from us faster than the speed of light and this gravity as well.
The observable universe is of finite mass and size, while the total universe is of infinite or finite mass and size. On a macro scale, the total universe probably looks similar. It's definitely not micro homogeneous or entropy would be infinite and heat death would have already occurred. Heat death won't be the biggest problem because of the likelihood of the Big Rip.