I understand upgrading from Windows 10 Home to Windows 10 Pro can be done from within in Windows by purchasing the a Windows 10 Pro key and then switching the activation key to the new key. Doing so essentially "unlocks" the Pro features that are already present; I'm not sure that anything new is downloaded from Microsoft during the upgrade.
That being said, are one's settings and overall configuration preserved during such an upgrade? Or are many settings, etc. returned to their defaults in the process?