I use Tasker on my Android devices to do this exact thing, but I'm not a iOS guy to know what might be comparable on that platform.
My Tasker task basically looks like this:
When the Tasker shortcut (an shortcut on the home screen with the
BlueIris app icon - so it basically looks like the BlueIris app) is pressed........
- If NOT connected to my home wifi or my parent's wifi (we have a full time VPN connection between the two sites so while I'm at their house, I have full access to my system as if I was sitting at my home)
- Launch OpenVPN and start my Home VPN connection
- Wait 3 seconds (to ensure the connection is completed)
- EndIf (so if I am at home or my parents home, the system skips the VPN connection and delay)
- Launch the Blue Iris app (which is set to automatically login - which is why there is a delay because if the connection isn't completed, the app will complain it can't log in)
I also have a "end task" that when the Blur Iris app is closed, it will close the VPN connection automatically
This means that within about 4 seconds of pressing the "BlueIris" icon on my home screen, I am looking at the camera feeds of my house - regardless of my location. When I move to or open another app, the connection is automatically ended.
This works perfectly and it is especially helpful on my wife's phone because she doesn't need to understand when and how to connect/disconnect to a VPN to see the cameras. It simply works when she presses the "BlueIris" icon on her home screen.