Example of how you can remove all EE3 events (and related data INCLUDING attendees) from your database. Uncomment line 16 to actually delete anything using this function.

tw_ee3_remove_events_over_a_year_old.php

<?php

global $wpdb;

$last_year = date('Y-m-d', strtotime( current_time('Y-m-d') . ' -1 year' ));
echo $last_year;

$sql = 'SELECT e.id event_id, e.end_date';
$sql .= ' FROM '. EVENTS_DETAIL_TABLE . ' e ';
$sql .= ' WHERE e.end_date < "' . $last_year . '"';
$sql .= ' ORDER BY e.id DESC LIMIT 200';

$events = $wpdb->get_results( $sql );

foreach( $events as $event ) {
	//event_espresso_empty_event_trash($event->event_id);
}