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;
}

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.