iPhone Camera 16x9

This is an answer for those searching for changing the default camera ratio from 4x3 to 16x9.

As of iOS 17.2.1, there is no way to change the default ratio, but there is a sloppy workaround. To be clear, as of iOS 17.2.1, the default is 4x3 and there is no way to change that. The workaround simply preserves the settings wherever you left them the previous time you used the camera, so if it was left at 16x9 it will be 16x9 again the next time it is opened. It is not the same thing as changing the default, but under certain use conditions it achieves a similar result.

Settings > Camera > Preserve Settings > Creative Controls > On

You do not have control over what the default settings are automatically reset to when each "Preserve Settings" option is turned off. This is probably what you were searching for. Sorry!