Cautious Hero: The Hero Is Overpowered but Overly Cautious

Seiya Ryuguin is overpowered but overly cautious. After being summoned by the breasty goddess Ristarte in an attempt to level up her godhood, Seiya spends his entire isekai'd life grinding out pushups and beating up other gods to max out his stats. The Demon Lord in another world can wait as Seiya gets swol. He's the Cautious Hero.