Good evening!

My '11 F-150 has been having steering problems lately. The steering wheel has a "jerky' "sticky" feeling and won't re-center itself when I turn to the left. After some internet searches and a couple Youtube vids, I'm pretty sure I have issues with the intermediate steering shaft (Ford part # BL3Z-3B676-A). Apparently, the u-joints at either end can go bad and lose their ability to turn smoothly, causing the whole steering shaft to bind. From what I can tell, the first step in diagnosing is to spray the u-joints with a penetrating oil, and if that seems to "fix" the problem, it likely means they are shot and the shaft needs to be replaced. I did this and it seemed to make a difference, so I think I'm going to replace it. The replacement looks pretty straight-forward, and I'm pretty sure I can handle it myself. My questions are:
- Does all this sound correct?
- If it IS the shaft causing the issue, is it possible for it to occur in only one direction (left only)?
- Can I trust non-OEM parts?
- If the answer to that last question is yes, what are some recs for a place to purchase?
- If this doesn't fix the problem, what's the next part I need to investigate to fix my steering problems?

I'm pretty sure anything beyond this steering shaft will be out of my comfort zone, and will require an actual mechanic. Any and all feedback is welcome and appreciated!

Cheers!