I think you might have overstated the harm of the “euphemism treadmill”. Where does that term come from? I see a lot of problems with it. I’m certain that the coinage of that term cannot be the end of the discussion, but you seem content to hang your hat on it.

Let me share one piece of wisdom (from Kierkegaard!) that has been kind of a tragic comfort that can help guide the tortures of ethical behavior: we are always in the wrong.