OP,
I am confused. If what you say is that you are streaming “from” your iPad. That is the problem. This probably means you are using communication from the iPad to the streamer… you do not want to do that. This is exactly what happens to me when I tried this. This is an Apple communication problem. You do not want to be using the Qobuz app on the iPad. You want to use the Marantz app on your iPad to control the Marantz. The Marantz should have an internal app to link up with Qobuz.
You want the Marantz to pick up the signal directly and use the iPad as controller. What model do you have?