Permalinks structure in Postie functions

I have a function which adds a post’s permalink as a custom field called ‘share_url’, like this:

//
// CREATE SHARE_URL CUSTOM FIELD - NON POSTIE
//
 
function create_share_url_customfield($post_id) {
	global $post;
 	$post_url = get_permalink();
	$post_url_sanitised = esc_url_raw($post_url);
	if ($post->post_type == 'post'){
		update_post_meta($post_id, 'share_url', $post_url_sanitised);
	}
}
add_action( 'save_post', 'create_share_url_customfield' );

It works well when posting via the admin area, but posts created via Postie Plugin are not updated. For that reason, I created a Postie function:

//
// CREATE SHARE_URL CUSTOM FIELD - POSTIE
//

add_filter('postie_post_before', 'add_share_url_custom_field');

function add_share_url_custom_field($post) {
         $post_url = get_permalink($post['ID']);
? ?      add_post_meta($post['ID'], 'share_url', $post_url);
? ?      return $post;
}

This works, but the share_url takes the form of the ‘Ugly’ permalink (https://example.com/?p=N).?

How do I ensure that the first function captures all posts, including those generated by Postie? Or, alternatively, ensure that the second Postie-specific function retrieves ‘Pretty Permalinks’?