You have some color management issues going on somewhere. We need details, screenshots, and color settings for your project to point to the exact problem. The iPhone 12 also has several recording options. Try fiddling with them.
I feel like the problem is within the iPhone settings because I am having issues with both Premiere and AE and I have tried with a variety of settings. I even tried downloading older versions of AE to see if that would make a difference. Does anything in these settings look off?