Just to make things more interesting I now have a problem of when using the cinnamon desktop sounds app, when you try to run a speaker test there is no sound. Checked both the builtin audio (headphone jack) and a usb speaker and no sound from either. Both work just fine from the command line using speaker-test.
Just as a double check that it was not a cinnamon desktop problem, I did a fresh install (on a different ssd) of dietpi and after
the initial setup steps used dietpi software to install a mate desktop. (after verifying that .asoundrc was correct ) saw the exact same thing, onboard audio selected but no output in the spaker test using the mate audio app. Command line worked fine.