I don't know how you performed the "clean install". If you did not use the official downloadable recovery image for your Surface, https://support.microsoft.com/en-us/surface-recovery-image please try that. Instructions for the upgrade process are at https://v4.hkg1.meaqua.org/en-us/education/windows/change-home-to-edu
If you still have issues, contact Surface Support for Business https://support.serviceshub.microsoft.com/supportforbusiness