You're actually the first one to solve it, well done!
I hope your world becomes happy as well :)
I also hope you find what makes you feel alive too ;)
At first I was hopping around on the black and white platform, looking for possible interactions (but didn't find them), walking all the way to the right and found that it was a reincarnation, and then I was at a loss.
At this time, I pressed "i" and suddenly found that the scene and bgm changed all at once (I was like "wow" at that time), and then looked for the possible interaction again (still didn't find it), and realized that it was still a reincarnation. Then I just jumped freely to different platforms without any purpose, listening to the bgm :D