I'm late to the party here. but this doesn't answer the question at all.
I am an org admin (very new to it hough). My users want to be able to customize their display name to be a nickname... IN TEAMS ONLY. how is there no easy way to do this? Especially since it is apparent that personal account users can do whatever they want? why is there no edit button in the display name area like so so many articles say there is? If it is available in a personal account level, there is literally no reason it shouldn't be available in an organization. and if it is, there needs to be a way to find out how to do that. like I don't know, searching for display name in the teams admin center? they don't want display names globally changed for their office accounts. just in teams.