Interesting question.
While I have not tried connecting my iPhone 11 to my IDA-16 via USB, I have connected my iPhone 6 to it via the headphone jack to RCA in connectors. I still have my old iPhone 6 and use it as a wired source (with my IDA-16) and as a Bluetooth source with other equipment. Have you tried attaching a Bluetooth receiver to an IDA-16 in order to wirelessly connect to the amp? [I know this doesn’t answer your question. Let’s see what Jason (RustydogLim) has to say about your question.]
Michael