Robert E. Lee overrated?

I have been going into a deep dive on the civil war recently, and have found many believe Lee to be the best general of the civil war. I know he took part in major victories, but was his attack on Gettysburg not a massive mistake? The union won the battle of Vicksburg around this time, seizing control of the Mississippi. Should Lee and the south not have retreated to the south to try to gain this back? Sherman later marches to Atlanta and further takes surrenders from the confederate armies. But could this have been slowed or stopped if Lee wasn't hellbent on his forward push into the north? Further losing control of the war. Mind you I don't know much so I could totally be way off. After this deepdive I am finding Sherman to be the real best general of the war. But would love to hear thoughts and discussions on this!

(Also any recommended books to read I would appreciate. Is Sherman's memoirs worth reading?