How to change the WordPress MULTISITE site SUPER admin username on DataBase

 Change The Username Like Single Website

• Once there you’ll need to navigate to your wp_users table1 and 
• change the ‘user_login’ for the effected user to something a bit more unique 
• than say ‘admin’ or ‘sitename’.
• Perfect. We’d be good to go if we weren’t a Super Admin. 
• If you try to access the role now you’ll see you don’t have access to your super admin privileges anymore. Not good.

Keep Super Admin Privileges

• The fix to this particular problem is a little more tricky. 
• You’ll need to navigate to your wp_sitemeta table and look for the meta_key ‘site_admins’ and 
• you should see something like “a:1:{i:0;s:5:”admin”;}” in the meta_value field. 
• All we need to do at this point is change that to “a:1:{i:0;s:12:”new-username”;}“.

NTOE:

• Basically you’re replacing “admin” with “new-username” and 
• since “admin” is 5 characters long and “new-username” is 12 characters long 
• we change “s:5” to “s:12”. That should do it. 
• You should now be able to login with your new username and still have network admin privileges.