Mine looks same as your tbh but I think yours may be slightly worse. I don't have uniformity issues until I hit like
For me the flaw is most prominent when displaying this video (linked below) at the 20% grey section at 0% brightness in a pitch black room. My edges are darker and centre is brighter. Curious to see if anyone in the same conditions has a perfect screen. A lot of people are running light grey and taking photos of it saying it's uniform. Mine is like that too, you have to display a darker shade to really show the issues.
There are plenty of high end OLED TV's out there that also exibit the issue so the argument that "oh I payed a fortune for this phone I should expect a perfect screen" may not the most accurate. OLED tv's cost 4 - 5 times as much and still have the issue. It really is a lottery at the end the day. If the manufacture threw away all the not perfect screens I don't think they could make any profit at all. Because the fact is under normal viewing conditions it's a non existent issue. If it is then yes return it.
Not saying that perfect screens don't exist out there I think they do, but I also think a handful of them will have uniformity issues and hence it's not worth returning. Might end up like you exchanging 4 - 5 times which I don't think it's worth it. Here is the link, sorry if I ended up triggering anyone.