If you are looking for the "best" write-ups or series that execute this "return to childhood" theme effectively, these are the standout titles: Mushoku Tensei: Jobless Reincarnation
Kedo, ima de mo watashi-tachi wa gaki ni modotte yarinaoshi o kanau. Otona no seikatsu o sutete, mata gaki no seikatsu o hajimeyou. Mainichi ga yasumi de, kurai wa asobi, asobi wa kurai. gaki ni modotte yarinaoshi best