There is a very(!) contentious argument to be made that Lee imagined that he could make Gettysburg a replay of Austerlitz. I’ll just leave it at that.
However, strategically, Napoleon’s tactic to engage the enemy on a wide front, with a rapid maneuver second echelon looking to penetrate the front at a weak point, showed its fatal flaw to the Americans because of the Civil War. Basically, if both sides do it, you end up with trench warfare.
Because of the Civil War, America learned this lesson, but Europe did not, which really mattered just slightly over 100 years later, when most of Europe learned the lesson, and 21 years after that, for the Russians, since they bowed out of WWI before learning their lesson.
And through the end of the Soviet Union, the Russians still hadn’t learned their lesson, using light and heavy helicopters in tactics similar to light and heavy cavalry, and even integrating nuclear weapons into Napoleonic tactics.
By World War II, the Americans had perfected the fire and maneuver technique that just shreds the Napoleonic tactic. Had Russia invaded western Europe, they would have put their military through a meat grinder.
Longtreet was right.
With 14.7 million military deaths in WWII, and 35 million total deaths in WWII, I would suggest that the Soviet Military had already been through a meat grinder. They lost over a million second lieutenants. Think who gets to become a second lieutenant. A bright young man with some education and signs of responsibility. That is the price they paid for their early alliance with Hitler against Poland.