Use Quicktime Player as a live monitor for iPhone X (and later model) video recording in landscape mode not working

There are already quite a few of reporting of the similar issue in the support communities, regarding QT live preview of iPhone screen in landscape mode not working, but seems few years past and still non of them get a solution for it.

Hopefully in this report provides adequate context of the issue and the iOS developers can treat it seriously and get the issue fixed soon.

First let's clarify the reproduce condition:

1) Device must be iPhone X and later,

2) Camera app is running in photo or video capture mode.

Expected behaviour: I want to use my quicktime player on macOS as a live monitor for iPhone movie recordings. When rotating the phone in portrait or landscape mode, I'm expecting the QT player live monitor window rotates following the phone's orientation.

This actually works fine with most of the apps except the built in Camera app. For example the built in Photos app works perfectly. Even the Camera app itself when switching to phone and video viewing mode the rotation of the QT preview window on desktop following the phone's orientation perfectly.

So the issue is actually specific to the iOS built in Camera app, in photo or video capturing mode. In this mode the app will force the QT preview window in portrait mode, no matter what orientation the device actually is. And this makes landscaping mode photo and video captured not usable in the live preview window, and the captured video file is also not useable unless post processing the video file with rotation, obviously users will not be satisfied by such solution :-).

Unfortunately using the built in Camera app capturing video might be the most popular use case when a user trying to use QT to capture movie from iPhone's screen. This make things worse and IMHO this issue do has significant impact to the user experience and should be treated as a high priority issue.

And for users who are seeking for a solution for now, hopefully you haven't trade in your old iPhone. Forget about the super powerful camera on your new phone, get your old iPhone back. I have an iPhone 6s updated to the latest supported iOS version (14.7.1), and the Camera works perfectly in landscaping mode. Looks like this issue could be classified as a bug introduced since iPhone X and only impacts iPhoneX and all the models afterwards.