>The fact elephants have 4 forward facing knees also prevents a gallop.

That's inaccurate. Elephants have knees and elbows that bend the same direction as any other mammal's.

This skeletal diagram is an easy illustration - https://imgur.com/HtrRcOb

And here you can see the elbow joint vs knees on a living elephant - this elephant has its elbows bent backwards as normal, and its wrists pressed against the ground as it's 'kneeling' to dig.