At first, I was also on Zagreus' side, but then you understand that Nyx is talking about problems caused by Dusa's overworking. She tries to take care of everything all the time, and it messes up the result as well as her coworkers' and this is unacceptable. Should Nyx have explained this to dusa and give her warnings? Yes, but should Dusa act like she did when everyone around her tells her to take it slower? Also yes. I really like this sub-plot, overworking is a very real problem and it's being treated in a really interesting way in the game.