A successful general, yes.
A great general, not really.
He was well above average as a strategist but many of his successes were because of the tactical generals he had as both advisers and implementers. He did well when he took the advice of his generals but in short order he began to take the sunshine pumped his shorts about how great he was a bit too seriously.
In the end his strategic instincts could not carry him through his near defeats and the debacle at Gettysburg.
Grant and Sherman were disparaged by the Army and politicians for too long. When Grant was finally given command, things changed. He was able to read and anticipate Lee and knew that he had to be aggressive and put on the pressure. Before this, his opponents were political generals like McClellan who were certainly subpar when compared to him and who were unwilling to take risks and fight. With Grant and Sherman he faced opponents who knew that to win, they had to fight and take risks AND learn from their failures. They were at least equal to Lee and that was proved out by the ending.
Lee was an honorable man who with reservation took the side of his traitor state over his allegiance to the Constitution.
“A great general, not really.”
Are you a great general? Plenty of actual great generals bear witness that Lee was a great general.
Winston Churchill, who knew a thing or two about history, labeled Lee the “noblest American”.
Maybe we should go a little easy on slave owning traitor generals from Virginia?