Can we stop being OCD for a sec?
Firstly these phones have super polished steel bands, with shiny bits all over.
These phones are also assembled by hand in a factory, sure CNC machines are used for chassis and what not, but the final assembly are still done by hand, and humans aren't perfect by any means, and these are just your mass produced yearly released electronics, they are not a one off limited edition piece of jewelry or whatever. Also most small smudges can indeed permanently get oxidized by the steel band especially if you get the white color with the silver non PVD treated steel band, but a bit of metal polish should remove the smuge marks and minor scuffs off (scuffs you can fel with your nails are probably too deep) also metal polish can only be used somewhat okay with the silver chrome untreated/unpainted steel band, and even so too much pressure will make more scratches than what you had to begin with, it is somewhat similar to polishing scratches off glass with Cerium Oxide or jewelers rouge compound
Finally, on my old iphone 11 Pro Max and at the time Apple's most durable glass ever claim, my iphone 11 pro max brand new out of the box was scratched near the bezel, and I had to do numerous exchanges before I got one that had less imperfections. Also, some so called imperfections on Apple devices could also include batteries, on my M1 MacBook Pro, brand-new out of the box the battery capacity was like 96%
At this point, I just came to accept minor defects on mass produced consumer products. We live in a world nowadays with mas demand on everything,especially consumer electronics, and companies are pumping out with whatever little capacity they have as fast as they can, QC will suffer, but since nose modern electronic devices aren't built to last forever anyways, the QC isn't going to get better, Apple knows it and we know it. Most of use will probably swap out for a new iPhone or iPad or Mac etc every 3 or so years, well except for some of you ballers and true enthusiasts out there who gets a new phone/tablet every year or every few months lol...
From my experience, minor minor scuffs (like the physical defects you get from Apple's out of box cosmetic issues) isn't going to harm the resale market on the private used markets such as Facebook Marketplace, eBay etc..
I just live with it as long as it doesn't affect the device's functionality.
If I had a yellow tinted screen, severe backlight bleeding or defective dead pixels or stuck pixels I would probably be exchanging it.
But for minor smudge or microscopic scuff on a already chrome like polished steel band, I'd just live with it since I would probably make more deeper and larger scratches on the steel band after a week or two of daily usage lol
Or for OCD folks who doesn't like to see fingerprints or scuffs, just buy a regular 13 with the anodized aluminum sides, which is extremely durable for minor scuffings, thought aluminum does tend to dent or have chunks missing if you drop it without a case. So there is a trade off between polished steel and matte textured anodized aluminum
I usually try to stay away from that kind of inspection.