How to build an exposed locality views filter

there is an option to group the exposed filter and then use contains "suburb name" as the name and value:

use Drupal\Core\Cache\Cache;
use Drupal\node\Entity\Node;
use Drupal\Core\Cache\CacheBackendInterface;

define('CLINIC_ADDRESS_LOCALITY_CACHE_KEY', 'sql_query_cache_key::field_clinic_address_locality');
define('CLINIC_ADDRESS_LOCALITY_CACHE_TAG', 'sql_query_cache_tags::field_clinic_address_locality');

/**
 * Implements hook_ENTITY_TYPE_update() for node entities.
 */
function soft4net_node_update(Node $node) {
    if ($node->getType() == 'clinic') {
        // Invalidate the custom cache tag.
        Cache::invalidateTags([CLINIC_ADDRESS_LOCALITY_CACHE_TAG]);
    }
}
  
/**
 * Implements hook_ENTITY_TYPE_delete() for node entities.
 */
function soft4net_node_delete(Node $node) {
    if ($node->getType() == 'clinic') {
        // Invalidate the custom cache tag.
        Cache::invalidateTags([CLINIC_ADDRESS_LOCALITY_CACHE_TAG]);
    }
}

/**
 * Function to execute and cache the custom SQL query.
 */
function soft4net_get_cached_query_results__field_clinic_address_locality() {
    $cache = \Drupal::cache()->get(CLINIC_ADDRESS_LOCALITY_CACHE_KEY);
    if ($cache) {
        return $cache->data;
    }
    else {  
        // SELECT DISTINCT `field_clinic_address_locality` FROM `node__field_clinic_address` WHERE 1
        $database = \Drupal::database();
        $query = $database->select('node__field_clinic_address', 'nfca')
            ->fields('nfca', ['field_clinic_address_locality'])
        ;

        // $query->accessCheck(FALSE);
        
        $results = $query->distinct()->execute()->fetchCol();
        // $result = $query->distinct()->execute()->fetchAssoc();
        // $result = $query->distinct()->execute()->fetchAll();

        \Drupal::cache()->set(CLINIC_ADDRESS_LOCALITY_CACHE_KEY, $results, CacheBackendInterface::CACHE_PERMANENT, [CLINIC_ADDRESS_LOCALITY_CACHE_TAG]);
    
        return $results;
    }
}

/**
 * Implements hook_views_pre_view().
 */
function soft4net_views_pre_view(\Drupal\views\ViewExecutable $view, string $display_id, array $args) {
    if ($view->id() === 'clinics' && $display_id === 'clinics_list') {
//         $field_clinic_address_locality_options = $view->getHandler($view->current_display, 'filter', 'field_clinic_address_locality');
// echo '<pre>';
// print_r($field_clinic_address_locality_options);
// echo '</pre>';

        $field_clinic_address_locality_options = [
            "id" => "field_clinic_address_locality",
            "table" => "node__field_clinic_address",
            "field" => "field_clinic_address_locality",
            "relationship" => "none",
            "group_type" => "group",
            "admin_label" => "",
            "plugin_id" => "string",
            "operator" => "=", // "and",
            "value" => "",            
            "group" => 1,
            "exposed" => TRUE,
            "expose" => [
                "operator_id" => "field_clinic_address_locality_op",
                "label" => t('City', [], ['context' => 'Address label']) . ':',
                "description" => "",
                "use_operator" => FALSE,
                "operator" => "field_clinic_address_locality_op",
                "operator_limit_selection" => FALSE,
                "operator_list" => [],
                "identifier" => "field_clinic_address_locality",
                "required" => FALSE,
                "remember" => FALSE,
                "multiple" => FALSE,
                "remember_roles" => [
                    "authenticated" => "authenticated",
                    "anonymous" => "0",
                ],
                "reduce" => FALSE,
            ],
            "is_grouped" => TRUE,
            "group_info" => [
                "label" => t('City', [], ['context' => 'Address label']) . ':',
                "description" => "",
                "identifier" => "field_clinic_address_locality",
                "optional" => TRUE,
                "widget" => "select",
                "multiple" => FALSE,
                "remember" => FALSE,
                "default_group" => "All",
                "default_group_multiple" => [],
                "group_items" => [
                ],
            ],
        ];

        // $field_clinic_address_locality_options['group_info']['group_items'] = [];

        $results = soft4net_get_cached_query_results__field_clinic_address_locality();
        array_walk($results, function($city, $key) use (&$field_clinic_address_locality_options) {
            $field_clinic_address_locality_options['group_info']['group_items'][$city] = [
                "title" => $city,
                "operator" => "=",
                "value" => $city,
            ];
        });

        $view->addHandler($view->current_display, 'filter', 'node__field_clinic_address', 'field_clinic_address_locality', $field_clinic_address_locality_options);
    }

}