Chapter 4 will be fully updated with proper storyline in 2nd stage two days later!
Edit: It's now available!
But first, here's a video showcasing all possible decisions you can make in this act (can be accessed in Bonus Map!).
Each path has a series of sidequests you need to complete to influence whatever happens in Chapter 7.
For example: In Amelia path, three sidequests in Chapter 1, 3 and 5 will affect the performance in Chapter 7, then the subsequent outcome will affect all future chapters, big or small.
For Final Chapter A, you also get the option to choose whoever to control as - the previous choices (both Amelia and Republic) will either decide how one will survive, or die in the end. Which means unlike Act II, there won't be a true ending - it's all up to you.
For Final Chapter B, the enemies you face in first stage also depends a lot on Chapter 7 assessment as well. And in 2nd stage, it'll also affect the outcome of Void Queen at the end (successful return to home, permanent stay or dead).