It's not a defect, it's physics.
You can exchange it, but the replacement will do the exact same thing.
You can try to figure out what's wrong all day, but I can all but guarantee that you will still be posting about this issue here this time next year just as the people on the iPhone 11 lens flare thread are, thirteen months after they were informed that it was not a defect but rather just… physics.
Once again, it is what it is, and there is no cost associated directly with the phone - Apple offers a full refund within 14 days of purchase. If there were carrier costs associated with switching phones, you will need to take that up with your carrier.
The phone's camera is working properly, you don't like how it works.
What you consider to be a "defect" won't change, no matter how much you want it to.
Once again, it's impossible to be more helpful and constructive than that; this is what it is and it won't be changing (but if it does, you can always buy one then and spare yourself however many months of anguish.)
I'm not trying to be insulting here, but you don't buy a steak and complain that it's not chicken, you have to buy what's right for you.