Hi Vincent,
This is programmable. As per USB standard requirements, 5V profile is mandatory, so you can't remove it. If only 20V profile is supported by your application, there is a tip: Just set the number of PDO to 2, and also tick the "POWER_ONLY_ABOVE_5V" option, so that your application will not be powered at 5V when negotiation ends with a 5V results.
An additional tip (in case you application can support less than 3A @ 20V): set the PDO current to the minimum workable (for instance 2.25A would allow to comply with 45W chargers, increasing the interoperability with universal chargers). By enable the REQ_SRC_CURRENT feature, this will make sure you application will always book the maximum current offered by the SOURCE.
Rgds,
Benoit