What happens if a person destroys all plants?

Following the destruction of plants, humanity will also disappear. Plants are the main source of oxygen on the planet, if people destroy all plants, they will very quickly run out of oxygen. Plants also serve as food for people and animals, when they are gone, humanity will starve, imagine: wheat, rice, corn, peas will disappear, there will be no bread, no potatoes, the main source of starch and vitamins will disappear. Without a doubt, without plants, the Earth will turn into a wasteland.