single events shortcode?

I guess the best way would be to create your own single-event.php which includes a different template file depending on whether the event recurs or not:

if( eo_reoccurs() ){
   include( ... ); //your template file for recurring events
}else{
   include( ... ); //your template file for non-recurring events
}

(Codex: https://codex.wp-event-organiser.com/function-eo_reoccurs.html)

(get_template_part() might actually be a more useful function to use here).