In crossover anime, who isn't a childhood friend?

Summary Starting in kindergarten, I got to know Yukinoshita, Hayasaka Ai, the Takanashi sisters...[Male protagonist, multiple female leads, slice-of-life story]Good news! Although I was killed by a dump truck, I managed to travel through time.Bad news: I've been transmigrated into the body of a five-year-old toddler.-My name is Yuan Qianye, and I am currently in the senior class of kindergarten.Even though my body has shrunk, I'm not panicking at all.Because my system has a "God's-eye view".Under certain conditions, it is possible to observe others without regard to the laws of physics.In addition, I can also bind with other people.I will also get a share of the improved skills they gain through hard work.Knowing this, the next step is quite simple...(This story blends the worldviews of several popular slice-of-life anime series, and provides detailed descriptions of each main character. Even those unfamiliar with the original works can enjoy it as an original story.)