Have you tried the current generation of iPhones? Same issues? Just wondering.
We're three generations past the iPhone 6 and its camera:
iPhone 6
iPhone 6S
iPhone 7
iPhone 8/X
I would hope iPhone cameras would be at least a little better now...
Yeah, I'm on a 7 Plus now. Everything looks like a paint by numbers watercolor. It's not bad when the images are small, but they're totally unsuitable for printing or even having as a desktop background on my Mac.