Hi there,
To list the categories, you might be able to do something like this:
add_action( 'generate_after_archive_title', function() {
$term = get_queried_object();
$children = get_terms( $term->taxonomy, array(
'parent' => $term->term_id,
'hide_empty' => false
) );
if ( $children ) {
foreach( $children as $subcat ) {
echo '<a class="button" href="' . esc_url(get_term_link($subcat, $subcat->taxonomy)) . '">' . $subcat->name . '</a>';
}
}
} );
The filters would likely require custom development as it’s quite complex.