I'm looking for a story where someone became their friend's new child. Preferably where the friend hadn't particularly been great to MC, and now the MC is a child they love with memories of things their parents wouldn't want them knowing. Let me know if you think it exists and any similar recommendations where the MC is reincarnated into the same world and knew his/her parents somehow. World setting doesn't have to be earth.
In otome game genre you get the “transmigrated “ mc who “saw”/“knew about” her /his (more rare) “new” parents through the computer/otome game she played in her life on earth before transmigrating. Most otome game genre novels have that scene in some shape or form.