MacOS is inherently a mult-user system, and can have any number of regular users Accounts and any number of Admin User Accounts. Every Admin user is equivalent in power to every other Admin user. There is no "Owner" account.
There is a procedure for changing the name of an Admin Account, but it usually results in Users being shut out of their Mac, with no way to log in at all.
Instead, create a new User Admin Account with a name you like, and copy any files you need from the old Admin User Account. if after a week or so you are not having troubles and are not missing anything, you can delete the old Admin user with the hateful name.
System preferences > User&Groups
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