Can I use a Live Photo for my wallpaper on a iPhone 12 Pro Max.

Correct. You can use a live photo, but the animation is not possible any more since the long press action now triggers the Lock Screen customization option in iOS 16. It will be just a static picture.

Can't have both things using the same action.

Can't i use the both things using the same action.

I one to use the both things using the same action.

No you have to change it to live wallpaper

Can you change it now to the live wallpaper

I would love to change it to this live wallpaper