How to search usermeta table

This works:

$WhoIsUser = get_users(
  array(
   'meta_key' => 'deviceid',
   'meta_value' => '45545'
 )
);

This returns the whole row for that user from the users table. If you print_r it out like so:

echo '<pre>'
echo print_r($WhoIsUser, TRUE);
echo '</pre>'

you get:

Array
(
    [0] => WP_User Object
        (
            [data] => stdClass Object
                (
                    [ID] => 123
                    [user_login] => userman
                    [user_pass] => $P$mBH8dpvhJD5xN8pk.
                    [user_nicename] => usermans
                    [user_email] => [email protected]
                    [user_url] => 
                    [user_registered] => 2020-05-11 14:36:24
                    [user_activation_key] => 157784:Fj8SR051xbzUVMpAFcYI0
                    [user_status] => 0
                    [display_name] => J B Gomez
                )

            [ID] => 123
            [caps] => Array
                (
                    [subscriber] => 1
                )
and so on....

To access just the ID I wrote this:

$WhoIsUser[0]->ID;