Lee resorted to exactly the same tactics at Malvern Hill and at Gettysburg. No genius military tactics there. Nothing to learn or study from the Confederate side in the Gettysburg campaign. One difference, by the end of the Overland Campaign Grant won his objective, the ANV was locked up like a tiger in a cage at Petersburg. Lee’s Gettysburg campaign ended with the ANV retreating out of Pennsylvania having lost 1/3 of it’s soldiers as KIA, MIA, captured or wounded. Another difference, AOP casualties, in the Overland Campaign, contributed to victory. Casualties in the ANV, during the Gettysburg Campaign, contributed to defeat. In war, victory is the only thing that counts, there is no second place award.
Anyway the US Civil War is studied by war colleges all over the world. Lee's infantry tactics are the universal standard.