Big A** Fan Matter driver request

Taking a quick look at the driver i think you are referencing when the method
attributeWriteRequests is used. That is a hubitat method that builds the list of attributes to send to the device.

Here is a thread i kind of brought up this point already. In that thread you see the supported data types that we were provied to use for Hubitat. 0x20 is not present in that list.