WP Query – Show custom posts only if user contain some user meta

You could approach in two steps. First get all the users that match your criteria

$user_ids = get_users([
    'meta_key' => 'activeacc',
    'meta_value' => true, // or whatever value you are storing
    'fields' => 'ID',
]);

and then run your WP_Query for only those users

$properties = new WP_Query([
    'post_type' => 'property',
    'author__in' => $user_ids,
]);

There is no need to set post_status => 'publish' since it’s the default.

Also would be possible to accomplish the same in just one query with posts_clauses filter but I will not develop it here.

See https://developer.wordpress.org/reference/classes/wp_user_query/prepare_query/ for all available arguments for get_users.