Variable redirect on User Registration

Hey,

So, I have a Forminator regsitration form that I want to change the redirect URL of, depending on the URL variable

I copied and changed this code thinking it would work:

<?php
/**
 * Plugin Name: [Forminator] - Custom Form Redirect
 * Plugin URI: https://wpmudev.com/
 * Description: Adds custom redirect to Forms based on submitted data
 * Task: SLS-183
 * Version: 1.0.0
 * Author: Panos Lyrakis @ WPMUDEV
 * Author URI: https://wpmudev.com/
 * License: GPLv2 or later
 */
if ( ! defined( 'ABSPATH' ) ) { 
	exit; 
} 
if ( defined( 'WP_CLI' ) && WP_CLI ) { 
	return; 
}
if ( ! class_exists( 'WPMUDEV_Forminator_CustomForm_Redirect' ) ) {
    class WPMUDEV_Forminator_CustomForm_Redirect {

    	private $form_id = 380;

        private static $_instance = null;

        public static function get_instance() {
            if( is_null( self::$_instance ) ){
                self::$_instance = new WPMUDEV_Forminator_CustomForm_Redirect();
            }
            return self::$_instance;
        }
        private function __construct() {
        	add_filter( 'forminator_custom_form_submit_response', array( $this, 'handle_response' ), 20, 2 );
        	add_filter( 'forminator_custom_form_ajax_submit_response', array( $this, 'handle_response' ), 20, 2 );
        }
        public function handle_response( $response, $form_id ) {
        	if ( ! $this->is_valid_form( $form_id ) ) {
        		return $response;
        	}
            if( isset( $response['url'] ) ){
                $response['url'] = $this->calc_url( $response['url'] );
            }
        	return $response;
        }
        private function calc_url( $redirect_url ) {

        	$new_url = get_bloginfo('url').'/checkout';

        	if(isset($_GET['redirect_to']) && $_GET['redirect_to'] == $new_url) {
				$redirect_url = esc_url($new_url);
        	}

            return $redirect_url;

        }
        private function is_valid_form( $form_id ) {
        	return (int) $form_id === $this->form_id;
        }
    }
	if ( ! function_exists( 'wpmudev_forminator_customform_redirect' ) ) {
    	function wpmudev_forminator_customform_redirect(){    		
    		return WPMUDEV_Forminator_CustomForm_Redirect::get_instance();
    	};
    	add_action( 'plugins_loaded', 'wpmudev_forminator_customform_redirect', 99 );
    }
}

The bit I edited is the calc_url() function, as that’s the bit in the original code that did the redirect URL change (I think)

The login/reg page has the URL variable ?redirect_to=https://mydomainnamehere.com/checkout on the end which is needed for something else and can’t be removed

Basically, I want the form with ID = 380 to redirect to that URL variable, but ONLY if it is present (hence the if statement in my calc_url() change above

Can anyone see why this isn’t working?