Select Paid Memberships Pro Payment Plan via query parameter

pmpro-payment-plan-select-plan-query-param.php

<?php
/**
 * Add &pmpropp_chosen_plan=<<plan_id>> in the URL to preselect the payment plan option.
 * Add this code to your site by following this guide - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpro_payment_plan_select_url() {
    // Only load this on the checkout page.
    if ( function_exists('pmpro_is_checkout') && !pmpro_is_checkout() ) {
        return;
    }
    ?>
    <script>
    jQuery( document ).ready(function() {
        const urlParams = new URLSearchParams(window.location.search);
        const payment_plan_query = urlParams.get('pmpropp_chosen_plan');
        const payment_plan_level = urlParams.get('pmpro_level');
        jQuery( "#pmpropp_chosen_plan_choice_L-"+payment_plan_level+"-P-"+payment_plan_query ).click();
    });
    </script>
    <?php
}
add_action( 'wp_footer', 'my_pmpro_payment_plan_select_url' );