Passing data from after_submission action to the confirmation filter in gravity forms?

I am creating a post within gform_after_submission action, which sets a post ID variable when the post is successfully created.

https://docs.gravityforms.com/gform_after_submission/

add_action('gform_after_submission_1', [ $this, 'create_order' ], 10, 2 );

public function create_order( $entry, $form ) {

    // get the current cart data array
    $data = self::data();

    // user id
    $user_id = get_current_user_id();

    // create an order array
    $order = [
        'post_author'   = $user_id,
        'post_content'  = json_encode($data,JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES),
        'post_type'     = 'purchase-order',
        'post_status'   = 'publish'
    ];

    // create order post using an array and return the post id
    $result = wp_insert_post($order);

    // if post id and is not a wp error then
    if($result  !is_wp_error($result)) {

        // get the id
        $post_id = $result;

        // my order custom field updates go here...

    }

}

Because my form is submitting via ajax, I can't invoke a header php redirect above because the redirect will just happen within the ajax request.

I need to somehow pass my $post_id to the gravity forms gform_confirmation filter. But I'm really struggling to see how this can be done.

https://docs.gravityforms.com/gform_confirmation/

add_filter('gform_confirmation_1', [ $this, 'order_confirmation' ], 10, 4 );

public function order_confirmation( $confirmation, $form, $entry, $ajax ) {

    // update redirect to order
    $confirmation = array( 'redirect' = get_permalink($post_id) );

    // return confirmation
    return $confirmation;

}

If anyone has any ideas that would be great thanks.