Differences/similarities between situation after Big Bang and before Big Crunch?

Modern physics is CPT symmetric, requires eternalism/Einstein's block Universe philosophy of time - assuming our Universe will finally collapse, the situation before such Big Crunch (BC) seems quite similar to after our Big Bang (BB).
It brings many questions (yellow), maybe also answers - I would like to propose to discuss. For example:

1) From entropy perspective, thermodynamical parameters like densities seem very similar near BB and BC - so shouldn't the final entropy be similar?
But if so, it means finally entropy should start decreasing - does it mean reversed 2nd law of thermodynamics near BC?
How would evolution backward from BC differ from evolution forward from BB?
What can we say about situation after BC, before BB (cyclicity)?

2) Currently synchrotron radiation mostly emits, naively against CPT symmetry, but usually asymmetry comes from solution - does it just mean it is now easier to find target for excitation in the future, than for deexcitation in the past?
Would it be the opposite before BC? I was inspired here by recent https://iopscience.iop.org/article/10.1209/0295-5075/ad2088/pdf suggesting such inversed beta/statistics in black hole.

3) Spontaneous emission seems to have similar asymmetry now - would it be reversed near BC?
Could they help each other by positive/negative radiation pressure/Feynman diagrams coupling them?

4) While after BB there is tendency to form black holes, shouldn't there be tendency to form white holes before BC?
Could they "survive till the end"? Rather lone - so how could we exclude/confirm that a lone shining point is a white hole? What spectrum should they have?
As white hole would act with positive emission pressure exciting atoms outside, shouldn't black hole act with negative radiation pressure deexciting atoms outside?