This isn't a new problem (I've since learned), and there's been attempted fixes (I guess they didn't work for me). But it's a great example of just one of the image quality problems that affect iPhone (and other phone) cameras. Phone cameras can't make it, for various reasons for various scenarios, so they fake it. Faking it has problems too, and now we're stuck between two bad options.
I'm glad people are talking about the frustration here, hopefully we'll see powerful options for wielding post-processing tech. When I looked up my problem there were a lot of people saying "this happens on every camera/phone, it's a law of physics and there's no solution".
https://discussions.apple.com/thread/252134950
https://www.indiatoday.in/technology/news/story/apple-may-fi...