After windows update I was having issue that could not find any reference to online, but was eventually able to trouble shoot. (updated Audacity after windows update and no change in behavior, now on 3.4.2)
Seems to have stemmed from computer having two speaker audio devices with the exact same name, and needing to have the second in the list order of options selected, but Audacity seeming to always go with the higher option in list regardless of which was selected. (probably the only thing that changed with the update was the order, since I think before updating selecting either had no effect but both worked so did not see as problem at time)
After renaming the one I needed to select in Settings > Sound > Device Properties; Audacity was then able to get the audio from desired source.