You’re Using Zoom Too Much
Your iPhone’s cameras are great enough on their own that you don’t really need to zoom in on any subject. In fact, some people might argue that you should never use zoom.
Sure, if you want to take a picture of something that’s far away, you can and should use it. But if you want to take more professional-looking photos, you should just rely on your iPhone’s cameras without any zoom. If you do need to zoom and you’re using an iPhone Pro, stick with the 2X, 2.5X, or 3X presets for your specific model, all of which use the telephoto lens.