I have a D/W for 4 years that does not clean any the upper rack. According to Whirlpool service, I needed a high loop drain to an air gap. The dishwasher is in an island. I added a high loop, and I still doesn't clean. You can see that the upper spray arm is not moving, but water is coming out of the holes.

Do I need an air gap? It's in an island so I can't drill through the granite top.
Any suggestions?

https://www.youtube.com/watch?v=75DB9cyPYO0

https://www.youtube.com/watch?v=iRCCrEwrst8

This is how you get your dishes cleaner no matter where you install your D/W.

I will further a guess that the screen in the bottom is full of gunk. Didn't watch the video but your problem is common to a partially plugged screen. Air gap has nothing to do with supply, only draining.

" a high loop drain to an air gap" that should read high loop OR air gap. The loop or lack of loop has nothing to do with your issue. You may have water coming out of the holes but it must gush out with force to make the arm spin. Its like a propeller. What model do you have?