Change 'Billing Details' title in checkout to be 'Account Info' when cart total is equal to ZERO

wcs_change_billing_details_string.php

<?php

function wcs_free_checkout_fields() {
    
    // Bail we're not at checkout, or if we're at checkout but payment is needed
    if ( function_exists( 'is_checkout' ) && ( ! is_checkout() || ( is_checkout() && WC()->cart->needs_payment() ) ) ) {
        return;
    }
    
    // Change string here
    function wc_billing_field_strings( $translated_text, $text, $domain ) {
        switch ( $translated_text ) {
            case 'Billing details' :
                $translated_text = __( 'Account Info', 'woocommerce' );
                break;
        }
        return $translated_text;
    }
    add_filter( 'gettext', 'wc_billing_field_strings', 20, 3 );

}
add_action( 'wp', 'wcs_free_checkout_fields' );