Yeah D-Day was a big failure. You surely know that.
Like most commanders of armies, Lee was not not primarily a "field" commander (neither was Eisenhower). He would plan the campaign and leave it to "field commanders" to execute the actual battle. For example, Lee made the decision to divide his army and send Jackson around to flank the Federals at Chancellorsville. How he got there and what he did there was left to Jackson. Lee was constantly having to plan how to attack the enemy while not letting them over-run Richmond (Lee did not think Richmond should be the Confederate Capitol). When one looks at how many times Lee successfully divided his forces, he seems to be an audacious commander. Much of the time, with limited resources, it was all he could do.
Eisenhower never commanded an army in the field.
Ike was a really good manager. Nothing wrong with that. But, it is what it is.