Exactly right regarding gain sensitivity. Volume is 0-100 and you can choose volume adjustments of:1,2,4,5,10,20 per click or button press. You also get to choose a natural or linear volume curve.

I have not had any issues with the Ethernet connection. Although I use that one a lot less than the one that is connected via WiFi.

You would be using the DAC in your tv the way you are describing your connection.