Windows guy here. I don’t know why it is only showing up as a MIDI device. You should be able to use the UR44 with Audacity on Mac. See here: Delay/Echo problem in output using Steinberg ur44
Are you using Audacity 2.4.2 ? Does Audacity have permission to use the microphone ? See here: Audacity 2.4.2 still not recording on Mac Catalina
I hope this helps. 