There are multiple third-party battery grips for Nikon Z6/Z7 cameras listed for sale on eBay with a shutter release button that connects to the camera with a cable. The original Nikon MB-N10 for the z6/z7 is just a battery pack and doesn’t have any controls. The new Nikon MB-N11 for the Z6II/Z7II does have controls (see this post for more information).
Addition al information on the Mcoplus vertical battery grip for Nikon Z6/Z7 cameras:
