How to activate internal mic during phone calls when using headphones with a USB-C to audio dongle?

I would like to use my *Samsung Galaxy S20* phone with my quality studio headphones for phone calls. Since the device does not have a 3.5 mm audio socket, I am using a USB-C to 3.5 mm dongle. The problem is that when the dongle is plugged in, the phone expects the audio recording to come from the headset's inline microphone, while disabling the built-in microphone. Is there a way to set the phone to use the internal mic while using external headphones through the dongle? I tried a couple of dongles and all have the same issue. Update: Phone is Samsung Galaxy S20, Android version 11, not rooted.