By The Grace Of The Gods (manga) 08

Slime's up for one recently deceased middle-aged businessman! When the gods reincarnate him in another world as a boy with magical powers, he discovers that magically-tamed slime are an untapped natural resource! In his past life on Earth, Ryoma worked himself to the bone as an employee of an exploitative company. Now, in Seilfall, the former office drone is the owner of a thriving laundry service. In fact, business is booming so much that Ryoma plans to open a second shop! Ryoma's days are fulfilling, but his time with Eliaria and her family is running out as their departure looms. The satisfaction of a new life well-lived makes him feel the ache of the coming loneliness that much stronger.