Hi,
When the installer finishes restoring the backup, the final step goes to a blank page and the configuration.php isn't generated.
In the final step, the installer tries to load Joomla\CMS\Encrypt\Aes. The constant JPATH_PLATFORM is undefined, and then the execution is stopped.
The installer isn't calling the JoomlaDetection getVersion to initialize the JPATH_PLATFORM constant.
If the JPATH_PLATFORM is defined previously at the top of the installation/index.php, the restoration can be completed successfully.
Best Regards,
Anibal