Restore from v2 backup folder from v3 upgrade

Your software Mautic 3.3
My PHP version is : 7.4
My MySQL/MariaDB version is (delete as applicable): MariaDB version

Updating/Installing Errors

The site is currently offline due to encountering an error. If the problem persists, please contact the system administrator.

*I am Updating
*Upgrading/installing via Command Line

These errors are showing in the installer :
None

These errors are showing in the Mautic log :
None

These errors are showing in the upgrade_log.txt file (located in the root of your Mautic instance when an upgrade has been attempted - ensure you remove or redact any sensitive data such as domain names in the file path) :

Nothing

Your problem
My problem is : The site is currently offline due to encountering an error. If the problem persists, please contact the system administrator. After upgrade failed.

how can I restore using the mautic-2-backup-files folder to recover from this crash?

Steps I have tried to fix the problem :