Ios 15.7 on Iphone 14 pro?

No that's not at all what I meant.

You said you saw a video showing how to downgrade. That is not possible on production iOS versions. If you saw a video showing how to downgrade, it was showing how to downgrade from a beta version.

I wans't telling you to downgrade from a beta version, I was explaining what you saw in the video

Now, you never mentioned using a beta version in your first post, no wonder you are having issues.

Follow the instructions below to remove the beta. It won't get you to 15.7 but it will put it back to the non-beta version.

How to uninstall iOS or iPadOS beta software - Apple Support How to uninstall iOS or iPadOS beta software - Apple Support

Apple doesn't support downgrading.

Regards

Giulio

I‘ve seen a video of a talking dog – but it was on the internet, so I’m sceptical. If you can successfully downgrade to less than what you’re phone shipped with, it will void your warranty.

What you most likely saw was them downgrading from a beta version, that is allowed. You cannot downgrade the production versions of iOS.

You can not install iOS 15.7 on any device that shipped with iOS 16.