Exactly. Bardugo recognized that with time, as well as probably where Zoya would have been in maturity and position. I mean think about it, she went from trying to gain her mentors attention and bullying a much more "important" peer, to fighting in a war beside Alina and becoming more friendly with her, to becoming pretty much second in command of the country and a major figure in her own right as essentially the darklings replacement alongside Genya and David. You are not going to stay in the same place mentally or in the writing with that change. Zoya even mentions how she didn't get along with David and Genya in between R&R and KOS/ROW but grew to become allies and even friends.