Just got back from the T-Mobile store because I had to go try this out for myself. I had zero problems taking photos of my 11 Pro Max with the main camera on the 12 Pro at normal distances of about 3-6 inches in not so great lighting. It focussed instantly where I wanted when I tapped the screen. It was only when I put my iPhone within a few inches of the camera that it wouldn't focus, which is pretty typical, but then it refocussed immediately as soon as I moved my phone back an inch or two. As Ive been saying, minimum focussing distance is a thing and its a little further for the 12 Pro, probably because of the LiDAR sensor.
So for those in here with issues, either you all have detective iPhones (which is unlikely) or you are trying to take photos/video at too close of a distance to your subject in low light. There is nothing wrong with the 12 Pro camera. Next.