Taxonomy overview list with exposed filter

I would like to alter the overview page of the terms in a vocabulary and add a filter. So I started to dig into the problem and stuck on the Vocabulary entity handlers.

By default, this is the handler that renders the overview page form : "overview" = "Drupal\taxonomy\Form\OverviewTerms"

I tried to alter the handler with the following code:

/**
 * Implements hook_entity_type_alter().
 */
function my_module_entity_type_alter(array &$entity_types) {
  $entity_types['taxonomy_vocabulary']->setFormClass('overview', CustomOverviewTerms::class);
}

The problem is that nothing really happens. I tried with altering other handlers like reset or delete and everything works well. What is the appropriate way to alter the overview handler?