After a few months of installs on different pc's Here's how to get rid of it on a clean 1903 install atleast Remove Ethernet/Wifi In my case i secure erase the ssd with a boot usb stick with parted magic first Setup a fresh 1903 install from usb Dont give it any internet connection at all once the install is finished and you are in windows run the registry key to disable provisioning reboot remove any bloat you desire gone / add your fav tweaks on first connection to windows update after a reboot the provisioning will be gone there is nothing do be done by the user it seem to be done on first connection to the internet after an os update hence the no connection is vital on setup of a fresh install otherwise you would have to wait for the 1903 - 1909 update
Upgrades don't get the setting, only clean installs. running the regkey in setupcomplete.cmd during OS install (clean install) should disable it. Or install a clean install with the last ssu/cu left out and run the regkey and install the latest ssu/cu and it will be disabled too.