Assign a template to a category with a plugin system and onAfterInitialise event

Question

I would like to assign a specific template for a certain category, I have tried with this code in a plugin system but without success (this code does not include the condition for the category I will do it afterwards.

<?php
defined('_JEXEC') or die;

class templateSwitcherCategory extends JPlugin
{
    
    public function __construct(&$subject, $config)
    {
        // Calling the parent Constructor
        parent::__construct($subject, $config);

        // Do some extra initialisation in this constructor if required
    }

    
    public function onAfterInitialise()
    {
        $app      = JFactory::getApplication();
        $app->setTemplate('protostar', null);       
        return true;
    }       
}
?>