Hi!
I’m just like you - one of those people who happens to noice every single little cosmetic defect, and sometimes it can drive me insane.
with that said, I have good and bad news for you:
the good news is that apple has an awesome return policy so if you decide to replace it you can, more than once even.
the bad news is that these are mass produced items, every single one of them will have some kind of defect somewhere, so you won’t get you perfect device. those who say otherwise are just blissfully ignorant.
with that in mind- I’d recommend you set yourself the bar for what is considered “unforgivable” - for me it is screen damage and things that are large enough that I see them during my everyday use of the device.
don’t forget to update on your decision and outcome, good luck!
the discoloration is probably because there is oil from your fingers on the area or it came into contact with water.
try to clean it with a damp microfibres cloth, if that doesn’t work try 70% isopropyl alcohol
it depends - how do you use your phone?
for example - if you know you will drop your phone, then otter box and the like are they to go.
for me personally - I’m extremely careful, the chances of me dropping my phone are very slim, but on the other hand, I do care about cosmetic damage, so my favorite is the apple silicone case - it offers only basic drop protection but it leaves almost no area of the phone exposed, and has microfiber lining that traps dirt and prevents it from scratching the phone