Lee’s handling of his forces at Chancellorsville was excellent. But to what end. He won the battle, the victory produced not strategic advantage for the Confederacy. As far as Gettysburg, What evidence? Lee’s original plan was to use of all of Longstreet’s Corp for the attack. That proved impractical, it would have stripped all of the troops facing Lee’s right flank, leaving it exposed. Pickett’s division was chosen because his division was the only major unit of the Army of Northern Virginia that had not been in combat at Gettysburg. The decision to attack Meade’s center on the third day of the battle was Lee’s and Lee’s along.
I won’t try to compete with the military pundits of FR, but it seems to me that Lee was (mostly) an excellent tactician. He often knew how to win battles that most other generals would have lost. But I wouldn’t rank him as a great strategist.
George Washington, on the other hand, lost a lot of battles. But Washington won his war. Because Washington was a heck of a fine strategist. Strategy is more important than tactics.