I had this problem aswell on my first 11 Pro Max.
The bottom and the wide-angle lens had dust particles under the glass.
At first when i got my 11 Pro max, i noticed right away that my ultrawide-camera was bit blurry on the edges. Didn't think about it, because couple of other people mentioned that it isn't "that" good. Couple of days later when cleaning the lenses i noticed the dust particles. Returned it and now my second 11 pro max is flawless. I don't know if its placebo effect but i think the "blurry" sides on the ultrawide is now gone on my second pair.
Couple of people argued that it doesn't matter, that the lens will be dusty anyway when you take a picture. Might be true, but when you pay top dollar or a device you don't expect it to have this kind of problem. When something like this passes QC, to me its a good reason to return the device.