Where did the universe come from? Atheistic origin science has no answer.

[Anomalocaris]

The thing is dark energy reversing would cause the universe to go crunch, but it won't reduce the entropy of the crunching universe.

Well... Like many other things in your known laws of physics... the second law of thermodynamics applies to what's inside the universe... it may not apply to the Universe itself.... it may not apply to a certain set of what we now call singularities.
We don't know that a big crunch would wouldn't reduce the Universe's entropy.
We don't know if the whole Universe's entropy just remains constant (in accordance with the second law).
It is fun to speculate, but not particularly straightforward to verify.

The thing is if you assume without any evidence that the laws of physics well validated in our universe no longer applies across the entire universe simply because those laws are inconvenient to your theory about the entire universe, then you reduce theorizing to wishful thinking, and your handiwork becomes no different for the special pleading used to defend Noah's ark.