Reborn as a Demon King, but I Just Want to Farm

[Japanese Western Fantasy + Business Simulation + Decent Demon King] What should I do if I am reborn as a demon king, my level is cleared, my city is destroyed, and I try my best but cannot defeat the hero? Go back to farming. Chosen by the dead Demon King, he uses the knowledge of modern people and the body of the Demon King to work towards the peaceful coexistence of humans and demons. Starting from scratch, from the first field to rebuilding the Demon King's City, from conquering the Goblin tribe to the unification of the world in another world.