I’ve tried several cables to connect to the TWA. Either I can’t get signal from the TWA to midi guitar or it just gets picked up by the iPad mic. I get sounds that playback from midi guitar to the TWA. I tried a usb-c to 3.5mm male adapter. I have an apple usb-c to 3.5mm female adapter then I plugged the TWA iDevice adapter and that still picks up sound from the iPad mic. Please let me know if I’m missing something.
Check out this customer made video on setting up the iDevice with the MIDI apps, you may need to turn the mic level down in one of the apps.