WooCommerce - Allow guest checkout for certain products when Guest checkout is Disabled globally

functions.php

/*--------------------------------------
Woocommerce - Allow Guest Checkout on Certain products
----------------------------------------*/

// Display Guest Checkout Field
add_action( 'woocommerce_product_options_general_product_data', 'woo_add_custom_general_fields' );
function woo_add_custom_general_fields() {
  global $woocommerce, $post;
  
  echo '<div class="options_group">';
  
  // Checkbox
  woocommerce_wp_checkbox( 
  array( 
	'id'            => '_allow_guest_checkout', 
	'label'         => __('Checkout', 'woocommerce' ), 
	'description'   => __('Allow Guest Checkout', 'woocommerce' ) 
	)
   );
  
  echo '</div>';
}

// Save Guest Checkout Field
add_action( 'woocommerce_process_product_meta', 'woo_add_custom_general_fields_save' );
function woo_add_custom_general_fields_save( $post_id ){
	$woocommerce_checkbox = isset( $_POST['_allow_guest_checkout'] ) ? 'yes' : 'no';
	update_post_meta( $post_id, '_allow_guest_checkout', $woocommerce_checkbox );
}

// Enable Guest Checkout on Certain products
add_filter( 'pre_option_woocommerce_enable_guest_checkout', 'enable_guest_checkout_based_on_product' );
function enable_guest_checkout_based_on_product( $value ) {

  if ( is_checkout() && WC()->cart ) {
    $cart = WC()->cart->get_cart();
    foreach ( $cart as $item ) {
      if ( get_post_meta( $item['product_id'], '_allow_guest_checkout', true ) == 'yes' ) {
        $value = "yes";
      } else {
        $value = "no";
        break;
      }
    }
  }
  
  return $value;
}

I've removed the
'wrapper_class' => 'show_if_simple',
line so that this will work on all product types now.

Guest Registration enabled does not remove the "Create an Account" option on the checkout page.

Since some have asked I've created the opposite scenario here to disable guest checkout on certain products when it is globally enabled:
https://gist.github.com/contemplate/5c1909bd1bfcd485cc1bdaf8786f3a80

This helped me a lot!
Here are the instructions on how to install this plugin using only the wordpress dashboard:
Just add the php tags (<?php {plugin code} ?>) and the metainformation comment. The comment is necessary for wordpress to recognize the plugin.
Here is an example:

<?php
/**
 * Plugin Name: Your Plugin Name (mandatory)
 * Plugin URI: Your Plugin URI
 * Description: A brief description of what your plugin does.
 * Version: 1.0 (mandatory)
 * Author: Your Name (mandatory)
 * Author URI: Your Website (mandatory)
 * License: GPL2
 */

   ...

?>

Save this as a .php file, store it in a folder and zip the folder. Then select this zipped folder, when you upload your plugin in the wordpress dashboard.

Adjusted script to only run on checkout by adding is_checkout() && to the condition. We'll see if this still produces desired results.