But phones aren't really that thin, especially with the camera lenses. Why didn't they just put the 3.5 mm jack on the other side from the cameras, protruding a little bit from the rear housing, exactly enough for the phone to rest stably on a flat surface without rocking?
The iPhone 14 has a glass case while the iPod Touch 4th gen had a metal case. That alone accounts for a significant difference in thickness of the internals of the device.