you’re down to the audio chain now.
radio
interface/cables
windows ‘settings’
you’ve got audio from the radio speaker so you know for sure you have a source.
is the din plug pushed in all the way into the radio jack?
audio settings in windows might need a tweak.
in the text box near the start/menu button of windows, type in mmsys.cpl
this should open up the ‘audio’ control panel.
on the recording tab, double click the ‘audio device’ that is the digirig.
under the various options, check the level, make sure agc is off. you may need as much as 90% on the ‘microphone’.
you can rename the device (and change the icon) to make it easier to identify as well.