I have never ever experienced anything even close to this bad on any previous phones- all of which have been flagship devices. Neither my iPhone 4, 6, 6 Plus, 7, OnePlus 5T or OnePlus 7 Pro had this issue at all. In fact, my 7 Pro could take amazing photos in all kinds of conditions and never once did lens flares like displayed in this thread appear. I believe it's a fundamental problem with the way Apple designs it's lenses, and that they pick form over function in this particular case- hence why they haven't done anything about it.
And your defense about "all flagship phones have it, you're using it wrong" isn't valid at all since not all flagship cameras have this issue- like my OnePlus 7 Pro for example. When paying over 1K on a phone, you have the right to expect the highest quality in all aspects compared to the lower priced competition which is doing it better.
That being said, I love everything else about the phone so far. I hope this is an issue Apple can fix with a software update (perhaps masking it out with A.I, like Photoshop does with it's healing tool).