Although Lee did engage in offensive operations at times, such as the Second Battle of Manassas (Bull Run) and the Battle of Sharpsburg (Antietam), these were primarily aimed at countering Union advances or achieving specific tactical objectives rather than as part of a broader strategy of invading the North.
Lee's commitment to a defensive strategy was influenced by several factors, including his assessment of the relative strengths and weaknesses of the Confederate and Union armies, the limited resources available to the South, and his understanding of the political dynamics of the war. He also recognized that a successful invasion of the North would require a level of manpower and logistical support that the Confederacy could not easily muster.
In summary, Lee did not significantly alter his strategy from a defensive war to an invasion of the North. He remained focused on defending the Confederate territory, repelling Union incursions, and conserving his army's strength.