Display is overlaying low opacity clones of the screen slightly above

@chao5uns sounds like you need a new display. We still need to see what yours shows so post some pictures of that with your question. Bilder zu einer vorhandenen Frage hinzufügen

Since iFixit does not yet have a guide for this, use something like this one instead. You can get a replacement display at plenty of online places, just make sure you buy the one for your phones specific version

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!

@chao5uns thank you for the picture. Yes, get a new display :-)