The Sadomasochistic Entanglement Between the Devil's Saint and the Upright Leader

I'm Looking for an Urban Harem Novel. If I Find It, I'll Give It a Try. Thank You.

I want to read a book like "The Idle Daily Life After Getting Rich". What is the author's name? I don't know, but there are some details. He has a shampoo shop in his house. The protagonist is reborn. He has a childhood sweetheart, but he was cheated on by her, and then