The missing memorized reports must be a QuickBooks problem, as it also happened to me. I have been using and upgrading QuickBooks for over 20 years.  This is the first time the memorized reports have quit working.  QuickBooks is requiring us to upgrade, and they are responsible for the many hours that it is causing us to rebuild the reports.  I did the "Re-Sort List", and some of my reports are back but not all of them.  This is very frustrating and time consuming.  I have several clients on my QuickBooks, and every file when restored had the issue.  There were no error when upgrading.  I also upgraded from 2018 to 2021.