The Events Calendar: Event Aggregator: All imported events set to a specific user as the Post Author.

functions.php

<?php

/**
 * The Events Calendar: Event Aggregator: All imported events set to a specific
 * user as the Post Author.
 *
 * Useful if all imported events are managed by a single WP User (e.g. verify
 * and cleanup), particularly if managed via the Community Events "My Events"
 * list of events.
 *
 * @link https://gist.github.com/cliffordp/4d4875f93ee9acf08584007c978919a0
 */
add_filter( 'tribe_aggregator_before_save_event', 'cliff_ea_set_author_for_imports', 10, 2 );
function cliff_ea_set_author_for_imports( $event, $record ) {
	// !!! change to the User ID you want this to be !!!
	$user_id_to_be_the_author = 4;

	$user = get_userdata( $user_id_to_be_the_author );

	if ( false !== $user ) {
		$event['post_author'] = $user_id_to_be_the_author;
	}

	return $event;
}