What you have been told is actually true. Your AMD Render only Device. Works the same way the old NVidia optimums laptops use to work. The Integrated GPU Driver has to be told what to do for each and every program. If the program is not defined it defaults to the Integrated GPU One of the reasons why In the old days NVidia Optimus laptops the dedicated GPU would stop working every time there was a Patch. Until the drivers were updated. NVidia changed the way the device was identified by windows to increase compatibility.
The fact is even AMD support does not know how their switchable GPU’s work. They have limited knowledge had to deal with them about a CPU issue Had a tech tell me that it was fine that the my Ryzen CPU was not stable at stock speeds unless it was at 1.5 volts Had to get a manager to get a RMA . the tier 1 techs you get are like any other company they use check lists to diagnose issues. They are suppose to escalate the ticket if they can not help you The GPU’s are designed by a separate division of the company in Canada. If you can either get support to escalate the tickets so you get a response from AMD Radeon. or try to contact them yourself.
A “Band-Aid” May be the only fix until Either the Laptop Manufacture releases Drivers or AMD releases drivers that have the new parameters for wow. It is likely if you complain enough to dell you might be able to get Dell Beta drivers that will work
The issue you are having is very common with AMD switchable GPU’s. Because of the way it is identified by windows.