PHP Fatal error: Class 'FreePBX' not found

I was in the process of upgrading from an earlier version of Freepbx using the system admin. I upgraded from 5.211.65-21 to 6.12.65-20 with no issues. I then upgraded to 6.12.65-21 and lost my ability to log into the gui. It just came up blank.
Reading through search results I have tried several things and probably made things worse. I ran the following on my system: rm -Rf /var/www/html/admin/modules/extensionroutes/
This allowed me to access the gui again; however, I’m not able to use the apply config button without getting a PHP error in the gui listed below.

PHP Fatal error: Class ‘FreePBX’ not found in /var/www/html/admin/modules/customappsreg/ on line 39

I am also seeing File does not exist: /var/www/html/admin/assets/dashboard from the httpd/error_log
I also disabled Endpoint Manager at this point from reading through other post on similar topics.
I have read where the PHP Fatal error Class FreePBX not found is a bad error so I was wondering
if I need to try to do a restore and start over or if I can do anything to try to save the current installation?

We are currently running on a backup version of the phone system while I try to upgrade the primary so I do have the original files from version 4.211.64-7 if I could replace anything that has been lost. Any help would be appreciated.