Presuming you're already reached out to your Ford dealer of choice, and they either didn't have one, or the price was out of reach, I tend to stick with RockAuto.com for such things. So many other places play the "back in stock soon" game on items that will never be in stock.
Fortunately for your car, they do seem to have all four corners available, but not as a quickstrut. And the prices don't seem unreasonable, for Motorcraft units.