I agree with pretty much everything here. The problem with the Avernus ending is that you don't keep "pushing and pushing and pushing" her to go back there. You decide if she goes during the very last cutscene. To frame the Avernus ending as a bad ending where Tav is a manipulative, egocentric dick that only cares about their feelings, not really thinking about their romance option / companion interests, it surely needs a build up or something.
There are several lines throughout the story where you can suggest that she consider going back to Avernus, so I think the set-up is there, light as it may be. But it's still not a satisfying narrative.
