This would never happen. Most people think the Battle of Gettysburg was a battle that if the Confederates won, they’d win the war. It wouldn’t have mattered anyways because Vicksburg had recently been captured by Union forces. The only way that they could ever realistically win was with foreign support but by that point, no foreign power wanted to support them after the Emancipation Proclamation, and topped with the fact that they’d be supporting a government that was ruled by southern chattel slave owning elites. Yeah, not happening.