More efficient TEC organizer dropdown at scale

tec_organizer_dropdown.php

public static function facilitatorSelect( $name, $current, $special = false){
            if( $special ) {
                $id = 'saved_organizer';
            } else {
                $id = str_replace(array('[',']'),'',$name);
            }

            $current_user = wp_get_current_user();
            $s = '<select class="chosen organizer-dropdown" name="' . esc_attr( $name ) . '" id="'.$id.'">';
            $s .= '<option value="0">' . __( 'Use New Facilitator' , 'tribe-events-calendar-pro' ) . '</option>';
            
            $my_organizer_ids = array(); // Holds a list of organizers were current user is the author
            
            // Grab a listing of all user's organizers
            $args = array(
                'post_type' => 'tribe_organizer',
                'post_status' => 'any',
                'author' => $current_user->ID
            );
            $organizers = new WP_Query( $args );
            $organizers = $organizers->get_posts();
            
          
            /*
             * Build user's My Organizers group
             */
            $s .= '<optgroup label="My Facilitators">';
            foreach( $organizers AS $o ) { 
                $my_organizer_ids[] = $o->ID;
                // Opening tag
                $s .= "\n\t";
                $s .= '<option value="' . esc_attr( $o->ID ) .'"';
                $s .= selected( $current, $o->ID, false );
                $s .= ' >';
                
                // Content
                $organizer_title = wp_kses( $o->post_title, array() );
                $s .= $organizer_title;
                
                // If we are in wp-admin we also need to show the email address
                if( is_admin() ) {
                    $s .= ' - ' . get_post_meta( $o->ID, '_OrganizerEmail', true);
                }
                
                // Closing tag
                $s .= '</option>';
            }
            $s .= '</optgroup>';
            
            
            // Grab a listing of the rest of the published organizers, not by this user
            $args = array(
                'post_type' => 'tribe_organizer',
                'post_status' => 'publish',
                'post__not_in' => $my_organizer_ids
            );
            $organizers = new WP_Query( $args );
            $organizers = $organizers->get_posts();
            
            $s .= '<optgroup label="Available Facilitators">';
            foreach( $organizers AS $o ) { 
                $my_organizer_ids[] = $o->ID;
                // Opening tag
                $s .= "\n\t";
                $s .= '<option value="' . esc_attr( $o->ID ) .'"';
                $s .= selected( $current, $o->ID, false );
                $s .= ' >';
                
                // Content
                $organizer_title = wp_kses( $o->post_title, array() );
                $s .= $organizer_title;
                
                // If we are in wp-admin we also need to show the email address
                if( is_admin() ) {
                    $s .= ' - ' . get_post_meta( $o->ID, '_OrganizerEmail', true);
                }
                
                // Closing tag
                $s .= '</option>';
            }
            $s .= '</optgroup>';
            
            echo $s;
        }