To show ICS and add to Google Calendar links for only logged in users use below method:

1. Create a folder in your child-theme/video-conferencing-zoom-pro/fragments/ if it does not exists.
2. Copy file add-to-calender.php from wp-content/plugins/vczapi-pro/templates/fragments/add-to-calender.php
3. To child-theme/video-conferencing-zoom-pro/fragments/

Now, open add-to-calender.php file from your child theme

Replace with below code after global $zoom

if ( is_user_logged_in() ) {
	?>
    <div class="dpn-zvc-sidebar-content-list vczappi-pro-ical-links">
        <a class="vczapi-pro-gcal-integration-link" href="<?php echo esc_html( $zoom['export_gcal_link'] ); ?>"><?php _e( 'Google Calendar', 'vczapi-pro' ); ?></a> / <a class="vczapi-pro-ical-integration-link" href="<?php echo esc_html( $zoom['export_cal_link'] ); ?>"><?php _e( 'iCal Export', 'vczapi-pro' ); ?></a>
    </div>
<?php } ?>

If you have already edited this file then just add is_user_logged_in() statement and wrap your code.