"If you can see the top layer of your Force Touch sensor" - How are we supposed to know whether we can see this or not? If one of your images shows us this then can you please point this out. Also, an image of what it should look like, without the problem would be good.

Just discovered this article you have posted about replacing the Force Touch Sensor. After looking at the article I can now see your first image, above, is showing the separated Force Touch Sensor. Perhaps you should link to it in this article, so people can get a better idea of what it is and what it looks like:

Apple Watch Vervanging van de Force Touch-sensor

Did you find out any details about the screw in the end?