Tried the same thing. The iPad Pro does not support the depth capture in iPadOS 15.0 Beta 5
I am really mad and disappointed that this app is so exclusive for iPhone 12 Pro/Max only. Also, does it make more sense to have M1 iPad as 3D model capture all in one, without even using Command-Line tools in separate Mac OS? It said it support M1 Mac so it is supposed to be available in M1 iPad, isn't it?