Edit index config (Search API) programmatically and get the status index updated

I have a site with 14 pieces of news and 44 basic pages.

1. I have created an index (Search API) with this bundle:

and this is the index status (the content is already indexed during cron):

2. When I edit the config, add the Basic page bundle and save it:

The index status is updated:

I want to do the part 2 programmatically. I tried two ways:

$index = Index::load('my_index');
$index->setOption('datasource_settings', [
  'entity:node' => [
    'bundles' => [
      'default' => 0,
      'selected' => ['news', 'page'],
      'languages' => [
        'default' => 1',
        'selected' => [ ],
      ],
    ]
  ],
]);
$index->save();

and

$datasource_settings = [
  'entity:node' => [
    'bundles' => [
      'default' => 0,
      'selected' => ['news', 'page'],
      'languages' => [
        'default' => 'TRUE',
        'selected' => [ ],
      ],
    ]
  ],
];
$search_index = \Drupal::configFactory()->getEditable('search_api.index.my_index');
$search_index->set('datasource_settings', $datasource_settings)->save();

The config is saved, but the status index is not updated:

I tried to use these codes:

Option 1:

$index = Index::load('my_index');
$index->reindex();

But the nodes number are not updated, and I lose the nodes indexed:

Option 2:

$index = Index::load('my_index');
$index->rebuildTracker();

Result:

Option 3:

$index = Index::load('my_index');
$index->clear();

Result:

So my question is: How to update an index config programmatically and get the index status updated like the UI does when you click the Save button. I tried to look inside the search_api module code, but I got lost :(

Thank you in advance.

You can update the configuration of the search index with the following code

use Drupal\search_api\Entity\Index;

$index = Index::load('my_index');
$datasources = $index->getDatasources();
foreach ($datasources as $datasource_id => $datasource) {
  if ($datasource_id == 'entity:node') {
    $configuration = $datasource->getConfiguration();
    // This will add the 'page' bundle to the configuration.
    $configuration['bundles']['selected'][] = 'page';
    $datasources[$datasource_id]->setConfiguration($configuration);
  }
}
$index->save();

After saving the index, automatically a batch process will be called, if the changes are submitted in a form. Otherwise you manually need to add the new items to the index or reindex the whole index. For manually adding the new items, you can for example use the following code

$tracker = $index->getTrackerInstance();
$entity_type_manager = \Drupal::entityTypeManager();
$node_storage = $entity_type_manager->getStorage('node');
// Get the IDs of the new items.
$query = $node_storage->getQuery();
$query->condition('type', 'page');
$new_ids = $query->execute();
$entities = $node_storage->loadMultiple($new_ids);
$content_entity_tracking_manager = \Drupal::service('search_api.entity_datasource.tracking_manager');
foreach ($entities as $entity) {
  // Index the newly added item.
  $content_entity_tracking_manager->entityInsert($entity);
}

This may only works if you just have a few hundred new nodes, because you otherwise will get a timeout. Thats the reason, why the indexing happens in the batch process.