Those are, as you said, side contents. Those are pretty much fillers. I don't want to charge people for that. A story cannot exist without an overarching plot, and Chapter 2 has been running on fumes in that regard. Chapter 2 isn't supposed to exist in the first place, but I had to finish the rest of the girl's arcs, which I'd left behind because of poor structuring.
I hear what you're saying, and I am sure as an artist and creator you'd like to move on, but seriously consider you could spend the next ten years updating this story world you've already created and would do nothing but make many fans very happy. The potential to continue this story really is huge.