You can't be serious. I have an iPhone 14 Pro and it takes the best photos of any smart phone I've ever had. At least as good, if not better than the Nikon D800 I sold. The 6s I had was junk compared to the 14 Pro.
You can't get a decent 5" x 7" image out of a 48 or 12 MP image? What are trying to do? Blow up a tiny portion of the full image? If yes, that would be true of any image from any camera.
I try to take every shot at 1x. It's the only setting that takes a 48 MP image. I also always shoot RAW.
Yes, it's more difficult to get a sharp image as the pixel density goes up on the same size sensor. It takes less camera movement to cause blurring. But any pro will tell you if you want truly sharp images, use a tripod. Especially in low light. But I have no trouble getting sharp images hand holding the phone when the subject is well lit.
Never assume the camera is going to focus where you want it. Touch the object on the screen you want to be the center of the focal plane before taking the shot.
Here's an excellent, lightweight tripod for iPhones or Android phones. The nicest part is it comes with a remote so you can trigger a shot without touching the phone. That's as still as you're going to get it. I use it for product shots all the time.
As far as settings, did you change anything in the Settings away from the defaults? You need to if you want the 14 to take the best possible images.
Settings > Camera > ProRAW & Resolution Control - turn it on.
Directly below that:
Pro Default - Change it to ProRAW Mac (up to 48 MP)
Then below that:
AppleProRes - turn it on for vastly improved video capture
