Not the only one. I was also surprised plugging in my usb-c headphones did nothing. Generally it should be noted that this is about headphones with an usb dac. There are also adapters and headphones that pass through analog audio over the usb-c connectors, and those apparently work. These are the open issues that have been reported so far: https://gitlab.com/ubports/development/core/packaging/usb-moded/-/issues/6 https://gitlab.com/ubports/development/ubuntu-touch/-/issues/1912 https://gitlab.com/ubports/porting/reference-device-ports/halium13/volla-phone-quintus/volla-algiz/-/issues/3