Most recent cars that I have had, not Mercedes I should add, have been able to accept a USB that contained a mix of my own mp3 files. Is this possible on the EQC late 2021 model? To be honest I can't even find a standard USB socket able to take a standard USB stick. Failing that, other than having my own music on a mobile phone what are the options, if any? Thanks, as always, for your experience.