While I like the subject and the way you have posed, the lighting on the camera left side doesn't work for me as the skin has no texture. I agree with your comment about the hair, that looks very strange and has no texture. It does not look like it can be fixed.
I'm puzzled by the hair. It seems to have no detail, and if so, it can't be fixed. I'm just curious how this happened. Did you edit the photo? this looks like what happens when one burns (darkens) and area with no or almost no detail--it just turns gray. If you didn't edit the photo, there must be something in the iPhone's automatic processing that did this.
Unfortunately, you have posted a very low resolution image and it's hard to make a definite assessment on it.
I know someone whose job it was to assess cell phone sensors and lenses and his comment to me was that they are all awful. The main criteria is to fit those devices into a very thin body that severely limits the lens designer's options.
The only thing that lets the manufacturers get away with it is that these images are generally viewed on the phones themselves, and the relatively small size of those screens helps hide the problems. Enlarge the images and issues like the pixel smearing we see here become more obvious. My slightly newer Samsung Galaxy S10 exhibits some of the same behaviour. I replaced the battery a couple of years ago and its starting to die again, so I suspect I will have to replace it in the next 12 - 18 months. While the lens and sensors have not improved, hopefully the latest and greatest software will result in better images.
I'm no fan of phone cameras, but this doesn't look to me like pixel smearing from the camera's limitations. The original, to the extent that one can see at such a small size, seems free of that problem, at least in the hair. In contrast, the processed B&W image has lost all detail in two areas of hair, and perhaps on some of the face as well.
These two photos don't look the same. The background behind Mickey in the B & W is very different than the one in the colour picture.
On second though, this could be the result of AI doing a terrible job of conversion to B & W.