opti-add-slider.php

<?php
/**
 * Plugin Name: Opti Add Slider
 * Plugin URI: https://prothemedesign.com
 * Description: Add a slider to the Opti header.
 * Author: Ben Gillbanks
 * Version: 1.0
 * Author URI: https://prothemedesign.com
 * Text Domain: opti
 */

function opti_add_slider() {

  if ( ! is_front_page() ) {
    return;
  }

  echo do_shortcode('[metaslider id="36505"]');
  
}

add_action( 'opti_after_header', 'opti_add_slider' );