Hi,
I've set up my Nikon Z to transfer images to ShutterSnitch on an iPad using the "Connect to computer" option in Network settings. I found it more reliable than using the standard "Connect to smart device" Wi-fi set up. For starters, it remains connected until you decide to disconnect, or the battery goes flat!
My Nikon has the EXPEED 7 processor and I believe you'll need this as a minimum. Sorry I can only upload three images to this forum, so I've combined screenshots below.
On your Nikon go to the NETWORK MENU and select Connect to computer. Then select Network settings. Select Create profile. Choose the default name (WLAN1) or change it, and tap OK on the bottom right. On the next screen choose Direct connection to computer.
The next screen gives you the SSID and Key (password) to connect your iPad Wi-fi to. I suggest saving this info somewhere. Go to your Wi-fi settings on the iPad and connect using the information.
Then go to your Nikon Network settings and tap on the new network you created to activate it. It will go green. (On some Nikons I had to have ShutterSnitch open when activating the network for it to connect.) Go to Network settings and select Options.
Change Auto upload to ON. Open ShutterSnitch and it should be connected to your camera. Optionally, save a Quick Connect (QC) setting in ShutterSnitch for each camera using the SSID and Key (you saved the info, right?).
That's it. You should now only have to go to the NETWORK MENU, tap Connect to computer, select Network settings and tap the profile you just created (default was WLAN1).
When finished, remember to turn off the network connection by tapping on End current connection.