List only parent attributes on woocommerce admin atrributes page

I would like to add option on attributes page screen options, to filter out only parent attributes. The main struggle is that I can't even alter the query... I tried actions: parse_query, pre_get_posts but it looks like these are not suitable for taxonomy query.

public function prepare_items() - doesn't have any hook to add more arguments...

Please point me to the right direction.