I think it's impressive that you can tell my iPhone is not working properly right off the bat.
I've been using the Microsoft Lens app for years, works great on every device except the 15 Pro. I work from home so I use my iPhone and iPad for scans, I know what kind of results I'm getting. That effect of blurring the edges of the shot happens while scanning documents, as well, since apperture is software-only, so the text on the top and/or bottom of the page will be ever so slightly blurred no matter what I do. Perfectly legible, but at least a bit blurred/out of focus nonetheless, while the text in the middle is sharp.
The scanning feature in the Notes app is far worse than Lens, because Lens at least allows you to zoom in and out, so as to influence the lenses used. The scan is passable as all of the text can be read, but still not as good as the 13 Pro, which didn't have these focus issues.