I thought Ulysses said that he would probably die if he tried.
Although between Joshua's skills, his super signature pistol, legendary toughness, Ulysses has nothing on him. Maybe Ulysses would stand a chance if he had his eyebots with him.
Ulysses states that he couldve tracked joshua down and killed him but it would have done no good as joshua earned his life.
But still he is basically saying joshua would have been no match in how he phrases it.