My current iPhone 12 is perfect. But my last iPhone, an iPhone SE 2020, had a small mark on the side of the frame that looked like the picture you posted.
When I bought an iPhone 8 years ago, it had a distinctly deep scratch at the top of the frame where one could see the metal. I luckily opened the box in the store and they exchanged it for a new one.
Have experienced when I bought an iPad Mini, when the first one came out, that it had a dent in the back cover - think the charger had given the back cover a pressure. I lived with that, even though I was not completely satisfied.
My iPhone 5 in matte black, had scratches in several places when I first opened it. But it was known very normal for just that model and that color.
Have many stories, but I have also opened many iPhone and iPad boxes over the last 13 years.
So you should enjoy your iPhone, it is more perfect than what could otherwise be of possibilities.