I have a 2008 with the 4.6. A couple of years ago, I was having issues with the power steering in which it was getting hard to turn and there was a groaning sound. I replaced the pump and the hose, but the issue never really went away. I noticed now that when the engine is cold, the steering feels fine, but as it gets up to operating temperature, the truck is hard to turn. If I raise the RPMs of the engine a bit by pressing on the gas, it gets a bit easier. The "new" pump is a RockAuto replacement, so who knows what I ended up with.

What should be my course of action regarding this?

 

Not sure if this will help you but try spraying the steering knuckles down with wd40 and moving it back and forth. I was ready to replace the steering system and then I sprayed the knuckles down with wd40 and wow totally fine.
I now keep them coated with white lithium grease.
This was on a 2004 BTW.