Umami content not created
The Umami demo: Content module is not found from Drush, nor is it visible in the list of modules, because it is set as hidden in demo_umami_content.info.yml. If you change the hidden: true line in hidden: false, you will be able to uninstall the module, and re-install it. This will execute again demo_umami_content_install(), which imports the content. 

/**
 * Implements hook_install().
 */
function demo_umami_content_install() {
  if (!\Drupal::service('config.installer')-&gt;isSyncing()) {
    \Drupal::classResolver(InstallHelper::class)-&gt;importContent();
  }
}


If that doesn't work, the alternative is re-install Drupal using Unami as installation profile.