change user name of admin

sschklar wrote:

How do I change the Admin Username on my MacBook Pro?

Many problems can arise here, not recommended. Caveat emptor

Change the name of your macOS user account and home folder

Users who try to modify an existing User using that article OFTEN end up locking themselves out of their Mac completely.

Best practice is to Create a NEW admin User, log in as that user, re-arrange files as needed, and after a week or more of not accessing the old user, it can be deleted.

Follow these instructions: Change the name of your macOS user account and home folder

You must follow them exactly as written. All of them. Omit nothing.