Start this command
rundll32 sysdm.cpl, EditUserProfiles will display the "User Profiles" window containing details about the profiles stored on this machine. The loading speed of this screen suggests that these data are stored somewhere locally as opposed to those generated on the fly.
I am trying to understand where these data have been located so that they can be retrieved programmatically as a query
Win32_UserProfile provides only a subset of data, and I am specifically looking for the size of the profile in relation to its manual calculation.