Chittai Ore no Makikomare Isekai Seikatsu

A middle aged man, exhausted from work, gets caught in a Saint Summoning and is reincarnated as a small child named Keita, alongside a troublesome high school girl. Despite his worries about this world, created by a goddess for amusement, he possesses overwhelming magic, past-life wisdom, and an irresistibly cute appearance. As a result, he’s cherished by those around him and enjoys a peaceful life under the care of the third prince.