What "dumb" cable did you have in mind? Because once you accept Lighting as the connector, there is no "dumb". You have USB and this is where you have to start

What "dumb" cable did you have in mind? Because once you accept Lighting as the connector, there is no "dumb". You have USB and this is where you have to start. You don't get DVI/HDMI signals, analog audio, or anything else.