所以，我通过WooCommerce挖掘，看看他们是如何做到的，最终使用了类似的东西。希望它能帮助到一些人。

$order_id = $_REQUEST['order_id'];
$payment_method = $_REQUEST['payment_method'];

$available_gateways = WC()->payment_gateways->get_available_payment_gateways();
if ( ! isset( $available_gateways[ $payment_method ] ) ) {
    return;
}

// Store Order ID in session so it can be re-used after payment failure.
WC()->session->set( 'order_awaiting_payment', $order_id );

// Process Payment.
$result = $available_gateways[ $payment_method ]->process_payment( $order_id );

// Redirect to success/confirmation/payment page.
if ( isset( $result['result'] ) && 'success' === $result['result'] ) {
    $result['order_id'] = $order_id;

    $result = apply_filters( 'woocommerce_payment_successful_result', $result, $order_id );

    if ( ! wp_doing_ajax() ) {
        // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect
        wp_redirect( $result['redirect'] );
        exit;
    }

    wp_send_json( $result );
}