Well, he did win. But, as time passed, Grant also had far greater resources, too.
Lee had advantages because he was fighting a defensive war and was forced take risks for that reason. When your risky move span out, you look even smarter.
I wouldn’t say grant was a more brilliant military tactician than Lee was, but he at least knew what was necessary to beat Lee, and didn’t hesitate like McClellan and all those other clowns did.
A lot of men had to die, and Grant knew that. But he didn’t retreat after heavy losses, which helped him eventually beat Lee.