What modern support would it have taken for Pickett to break through at Gettysburg?

I said no air strikes.

15-20 riders with ARs and body armor would do the trick. But, I would attack at night with night vision and use foot soldiers.

3 M777.

Satellites

Modern support? Any mode of motorized transport to move troops would probably be enough.

Hell at wars close the Gatling gun was avail. A few of those could’ve turned the tide quickly.

Competent Confederate artillery would have helped.

After the initial rounds neither side could see that other due to all the smoke from the cannons. The Confederates were firing over the Union infantry lines and did not know it. The Union stopped firing back to cool their cannon barrels before the inevitable infantry charge. When they did Col. Edward Porter Alexander who commanded the Confederate artillery thought the Union artillery had been taken out. That and the fact that he was running out of ammunition caused him to tell Longstreet to charge at once or he could not provide artillery support.

Alexander's mother was a Hillhouse as was my grandmother. He and my great great grandfather were cousins.

Greek fire

Just modern automatic weapons would have been enough

Add in a few RPGs and it’s game over

You don’t need to go from 1860s to present. Hitting fast forward a little over 50 years give you WWI tech. A couple of “land ships” would have broken through the lines.

But even less than that. Gatling guns were civil war tech. Patent in 1862