How can I delete IOS 14.7 from my iphone system?

How can I delete IOS 14.7 from my system?
I have downloaded but not installed. I think it’s corrupt as it will not install.

And whatever the iOS update is at it’ll stay that way, doing a factory reset won’t downgrade the iOS software either.

You can’t. All you can do is factory wipe the iPhone and restore it, but make sure you backup your stuff to the iCloud first and make sure your iCloud has enough storage space for it.