After the upgrade to Atlassian Account, administrators are not able to edit the full name/display name of the user locally in the instance. It will adopt the full name of the user from https://id.atlassian.com

However, there will be time where we would like for the name to appear differently in different instance. This would especially be the case if a user will have an account in another instance as a "Client" or a "3rd Party" with my company name as label in order to differentiate myself from others.