Good work Luke.
This reminds me of when I had an Oldsmobile Intrigue as a daily, bought it used with 75K on it, 20 yers ago now. Had the 3.8L V6, great engine, was still running good at 180,000 miles when I sold it. Anyway, it developed a loud whine noise coming from the power steering, wasn't all the time, but would get very loud all the sudden and power steering would get weak.
I drained and put in fresh fluid and a new belt...still did it.
So I changed the power steering pump....still did it.
So I changed the whole power rack and pinion and blew out the hoses......still did it...
I'm thinking, the only thing left is the hoses/lines at this point.
So I changed those, thinking, this has to be it...still did it!
At this point I was back to square one, everything was replaced, same problem.
I started thinking, when you get a new pump for those you put back on the old reservoir with the metal clips, which I had drained and flushed out, but I decided to check it again...and I when I looked down in there with a flashlight after removing it from the pump and draining it, I found one of those paper/foil caps that's on top of the fluid bottle when its new, someone had dropped it in there, and it was lodged in there, and then the pump would suction it over the inlet, and starve the pump of fluid. So the entire time I was replacing everything, the problem was a little piece of foil paper that someone had dropped in the fluid reservior before I bought the car and it didn't show up right away.
We need a head slap imoji.