Cloning site and $config_directories
I don't know what you try to do with the config directories.

This doesn't make sense at all, setting a value and deleting it:

$config_directories['staging'] = 'sites/default/config/staging';
$config_directories = array();


The config directory staging does not exists anymore, it must be from an old drupal 8 version. You only need sync. This can be any directory. The hash is only for security reasons and is not needed outside the public files directory.

And I don't see anything in your workflow that would need a special configuration of the config directory, because you transfer the config in the database.