Normally to control a heater with a Duet you would need an associated thermistor sensor as well to complete the control loop.
If the heating panels are intrinsically safe to use without a thermistor, you could use relays to simply power them on and use the Duet to control the relay.
You could configure the heater pins as i/o control pins and use the heater outputs to switch the DC-DC relays on and off.
https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m42-switch-io-pin
Does that make sense?