Following the "user name formats" documentation, configuring the user name format to use {nickname|firstname} should change the display name across the platform for our users, pulling from the preferred name field if there is a preferred name, then using first name if there is not a preferred name. While it does behind the password in most cases, it does not change the fact that the "firstname" is always displayed on the front-end public-facing site. This should be fixed as it has an impact on how the students prefer to present themselves and how they are known by their community.