Change Drupal 10 search results to sort in date order DESC.

drupal10_search-results-sort.module

<?php
/**
 * Implements hook_query_TAG_alter().
 *
 * Orders the search results by the changed date in descending order.
 *
 * @param \Drupal\Core\Database\Query\AlterableInterface $query
 */
function mymodule_query_search_node_search_alter(\Drupal\Core\Database\Query\AlterableInterface $query): void
{
    $query->orderBy('n.created', 'DESC');
}

/**
 * Implements hook_preprocess_search_result().
 *
 * Preprocesses variables for the search result template.
 *
 * We want to show the created date and not the updated date for nodes 
 * that are in search results. We're adding a new variable to
 * use in the search-result.html.twig template.
 *
 * @param array $variables
 *   The variables array for the search result template.
 */
function mymodule_preprocess_search_result(array &$variables): void {
    if (isset($variables['result'])) {
        $node = $variables['result']['node'];

        if ($node) {
            $variables['created_date'] = \Drupal::service('date.formatter')->format($node->getCreatedTime(), 'long');
        }
    }
}