Drupal 8 delete menu link programmatically

Here's a snippet on how to delete all links in a menu.

// Need to replace 'sidebar-menu' menu name value with own name.

$mids = \Drupal::entityQuery('menu_link_content')

      ->condition('menu_name', 'sidebar-menu')

      ->execute();

$controller = \Drupal::entityTypeManager()->getStorage('menu_link_content');

$entities = $controller->loadMultiple($mids);

$controller->delete($entities);

For delete all the links in a particular menu like footer

$old_menu_links = \Drupal::entityTypeManager()->getStorage('menu_link_content')

  ->loadByProperties(['menu_name' => 'footer']);

foreach ($old_menu_links as $old_menu_link) {

  $old_menu_link->delete();

}

For update to  existing menu

$menu_links = \Drupal::entityTypeManager()->getStorage('menu_link_content')

  ->loadByProperties(['menu_name' => 'footer']);

foreach ($menu_links as $menu_link) {

  if ($menu_link->gettitle() == 'old-title') {

    $menu_link->set('title', 'new-title');

    $menu_link->save();

  }

}