Tested in Unity version 2021.3.33f1 LTS on an iPhone 15 Plus.
Screen.dpi is returning 326 instead of 460, a pretty big difference which makes its screen prediction the size of a 10 inch iPad.
Also UnityEngine.iOS.Device.generation will return iPhoneUnknown for the iPhone 15 family and the following will result in a compilation error if included in code:
DeviceGeneration.iPhone15
DeviceGeneration.iPhone15Plus
DeviceGeneration.iPhone15Pro
DeviceGeneration.iPhone15ProMax