Hi Nicholas,
I would like to explain that, some profile settings are not feasible to be changed at Basic Information, such as Name, because they are stored at the central database and essential for many other functions.
As the global admin to modify the properties, please go to SharePoint admin center > user profiles > Find profiles to find your account > click on your account > Edit My Profile.
And you may further turn to Office 365 admin center > USERS > Active Users > select yourself > EDIT > Details to manage your profile.
For more information, please refer to View and edit your profile and Add and edit user profile properties.
Thanks for your understanding and efforts.
Best Regards,
Rene
