How to change "Game Personas" name?

mariakoalart​  I believe the game persona listed under "The Sims" is for the old Sims 3 site: http://www.thesims3.com and store.thesims3.com.  (The Sims 4 logo is misleading here.)  You can't change this username, unfortunately.  Even EA customer support no longer has the ability to do so.

The good thing is that this username has no effect outside Sims 3: the website and your in-game username if you use any of the online features like Simport.