Have you already checked in "Setup (gear symbol) > Audio > Audio Device" whether your audio interface is displayed (and activiated) there? As with Cubasis 2 on my iPad4, "iPad Microphone" may still be activated there by default.
I am running the latest version of iOS, 16.3.1. It is running on an iPad Pro 12.9 inch 2nd generation. I did a search for “audio” in the settings, and there is no Audio Device sitting listed. The only audio settings I see are under Accessibility.
I have the AudioBus app, and I have it set to direct all 5 of the 8i6 stereo audio channels into Cubasis 3.
I can see in the Genos mixer that sound is being produced (the green indicator lights up), but that digital audio is not getting into Cubasis 3 for whatever reason. On the Genos in Line Out, all of the audio outputs are directed to Main.