When multiple rocketship carousel sections are present, the first section's settings will be applied to all of them

The approach looks good to me, I just have one observation:

+  use Drupal\Component\Utility\Random;

+  $random = new Random();
+  $key = $random->string('10', TRUE);
+  $build['#attached']['drupalSettings']['rocketshipUI_layout_carousel'][$key] = $this->configuration;
+  $build['#attributes']['data-carousel-id'] = $key;

To me Random.php seems to be quite heavy to generate IDs,
maybe we could replace it with Html::getUniqueId:
https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Component%21Util...

it's also using static cache and ensures that we generate unique ID per single page scope

Automatically closed - issue fixed for 2 weeks with no activity.