How to run a cron queue programmatically?
For one of my project, this worked for me :-

$queue_machine_name = 'sync_product_list';
$queue = \Drupal::queue($queue_machine_name); 
$queue_worker = \Drupal::service('plugin.manager.queue_worker')-&gt;createInstance($queue_machine_name);
$item_id = '123';
$queue_worker-&gt;processItem($item_id);