Hi Smiffy151no,
I am Dave, I will help you with this.
Yes, you can downgrade to Windows11Pro using a product key, that is sut a matter of entering the Pro product key and the system will convert to the Pro edition from the Enterprise edition and that will not affect the users files settings or installed software.
The method to use the generic key is usually if there is a pre-existing Pro licence on the PC, but that would also work to downgrade form Enterprise to Pro, then you would need to enter your legitimate Pro key to activate the Pro edition.