Got the phone back. First it was "repaired" on a local service and they didnt do nothing to it (they originally said that they would replace the phone to a new one...) and then they send it to Ireland (Apples international service). Phone was more than two weeks away....
And what they did?? Replaced the screen! Of course this didnt solved the problem and now the screen sounds loose when pressed from the right upper corner. So dissappointed because old days whole service process was so much faster and reliable.
Now I have downloaded Adobe Lightroom mobile from App Store and took pictures in raw a format (saved to camera roll in a jpeg after editing in Lightroom) and image quality is superp! Of course you get a lot of noise, but image detail levels is so fantastic so I dont mind it. So this is definitely a software problem, not hardware. Taking pictures like this and editing takes a alot of time so this is not a fix to my wife and usual consumers:(
When taking pictures with iPhone native camera application software is compressing images too much and is adding way too much noise reduction and also image manipulation. Could it be that Apple uses same algoryhtm with DCI-
P3 Wide Color Gamut than old phones and it makes this watercolor effect?