Gettysburg as the end all & be all of the Civil War was a product of Jubal Early & the Southern Historical Society. The elevation of Lee, Jackson & Joe Johnston to the status of military demigods was also a product of decades of the SHS's counter factual narrative. Superior Southern manhood was overwhelmed by hoards of deluded emigrants only fighting for money is another one of their tropes. Needless to say, the right to hold other human beings as property was, in the SHS version of events, a vague, peripheral issue. It was an amorphous "state right that the morally superior exemplars of white manhood fought for.
Lee's "invasion" of Pennsylvania was an unsupported raid that terminated in defeat at a meeting engagement at Nowhere, Pennsylvania forty one miles north of the Potomac River. Those are the facts. Compare that with the Tullahoma Campaign that has not even been mentioned in this thread.
June 28, 1863, Rosecrans' Army of the Cumberland faced Bragg's Army of Tennessee over a front stretching almost 60 miles wide, east to west. At the end of day one, his front was over 70 miles wide. In a matter of weeks, his army controlled all of Middle Tennessee & the absolutely strategically vital rail & mineral riches of Chattanooga 100 rail miles from his starting position. That is what a turning point looks like… but it is just a point. Campaigns, not turning points win wars.
From where Lincoln sat, at the end of the fighting season in December 1863, his army was victorious in a campaign that stretched from Cumberland Gap to Knoxville to Chattanooga to Vicksburg to Little Rock to Port Hudson, Lincoln's Campaign of 1863 effectively destroyed any avenue for CSA victory.
As Lincoln contemplated his war map in January 1864, it was a matter of how & when the war would be won, not if it could be won. That is what a real turning point looks like.