Are you saying that if a lot of negative experiences accumulate in all incarnations, then positive experiences begin to develop for balance? That is, if everything is blissful and joyful in all worlds, then it must be balanced with a certain amount of suffering for equilibrium?
You are introducing human judgments into this. Strive to think not as a human. As you are taught, think like a god. You are the artist of reality. You choose the colors with which to paint the canvas of the universe on its own canvas. When an artist paints, they add different colors. And when looking at the whole picture, they indeed add shadows and outlines in some places, and more colorfulness in others. Does that make the painting worse? Or should the artist consider whether the parts of the canvas where black paint needs to be applied dislike it? This is, of course, an exaggerated example, but it is an example of shifting from the thinking of the canvas to the thinking of the artist. From human thinking to God's thinking. As long as you cannot grasp the entire picture, your thinking will resemble the "thinking of the canvas." The canvas does not know what the painting should be. It judges from the perspective of a part.
Can parallel incarnations somehow influence each other? Suppose both are faced with a similar situation at the same stage of life. Let's say there are two ways to resolve it. One incarnation made its choice, but it turned out to be unsuccessful. The other was still contemplating, taking no action. And suddenly, it gets a feeling (intuition) that the issue should be resolved in the second way, not the first. How does this interaction happen? After all, intuition is nothing more than knowledge already tested by the Higher Self or your copy.
The interaction occurs quantumly. For the sake of your understanding, you can imagine a shared library. Or computer files that are constantly being added to, and all users of that computer have access to them. In this analogy, the computer is YOU, and the users are your current self and all the other parts of YOU. Intuition is a broad concept for you. You could say it is a fleeting sensation of your Wholeness with the other parts, breaking through your separation and lack of faith in your unity. In these brief moments, you hear the other parts of YOU. And not just intuition. Unexplainable fears. Insights.