Extracting Channel Data from fetch_feed()

The official WP docs say it returns a SimplePie object and the very first example in the SimplePie documentation is:

// Single feed
$feed = new SimplePie('http://simplepie.org/blog/feed/', $_SERVER['DOCUMENT_ROOT'] . '/cache');
echo $feed->get_title();

https://simplepie.org/wiki/reference/simplepie/start

$feed is the same type of object as the return value of fetch_feed:

Return

SimplePie|WP_Error SimplePie object on success or WP_Error object on failure.

https://developer.wordpress.org/reference/functions/fetch_feed/

Just make sure to call is_wp_error to check for failures