Let me ask you this. If the situation was reversed, do you think that Lee would have hesitated for a moment to use the same tactics Grant did if he thought they would bring victory?
Basis Lee's piety versus Grant's hard drinking (costing him rank in 1854), I would say a pure war of bloody attrition was not something Lee would do.
His campaign into PA was to get a decisive victory - getting France to recognize the South - and end the war.
If the situation were reversed, Lee wouldn’t have been invading another country.