I don't think it is fair to say that right now. A current Democrat would call Trump the worse and a MAGA person would call Biden the worse.
Jimmy Carter was a coherent intelligent man. You may not have liked his policies, but next to both these guys he looked like the smartest man in the world.As stated before, you need more deep analysis of history before you can make that call.
I would say since Television, Jimmy Carter was the worse.