When we back up your Microsoft 365 data, we add the same user that you entered on the authentication page as the Site Collection Admin of the SharePoint site. And when we back up Groups/Teams, we sometimes - when we encounter issues while getting data from Microsoft - add the user as the Owner of the Group/Team.
Instead of using an actual person account who is a Global Admin, we recommend using a Service Account (that has Global Admin permissions).
A Service Account is recommended by Microsoft to use for automated processes and system interactions within the Office 365 environment.