By default, on Windows 10 devices which are Azure AD joined, the user performing the join is added to the Local Administrator group. Besides the user and the local administrator (which is disabled by default), two other SIDs are added without any friendly name which explain who they are. So where are those SIDs coming from?
It is possible to make the user a normal user while enrolling the device, but then you have to create a Deployment Profile and use Windows Autopilot. See: Configure Autopilot profiles or use Bulk enrollment. See: Bulk enrollment for Windows devices
Note: This post reflects the status of Azure AD local administrative privileges as of February 11th 2020. Functionality may change, even right after this post has been published.Read More