If you are attending meetings for which you have previously registered, your name in those meetings can sometimes be locked to the name you registered with for that meeting. Changing your name in your profile later does not reflect in your prior meeting registrations, in many situations.
Admins can also set your display name based on Active Directory. Depending on how often the Zoom accounts synch with AD it will override changes by the user. We had this issue at first as the setting was editable by end-users and would revert back after syncing. I'm not sure what was changed as I was not part of the group at the time, but it is now locked and names map at every sign-in.
***Sometimes going backward is the only way to move forward.***