add_filter( 'woocommerce_subcategory_count_html', 'bbloomer_category_price_range', 9999, 2 );

function bbloomer_category_price_range( $html, $category ) {

$min = PHP_FLOAT_MAX;
$max = 0.00;

$all_ids = get_posts( array(
'post_type' => 'product',
'numberposts' => -1,
'post_status' => 'publish',
'fields' => 'ids',
'tax_query' => array(
'relation' => 'AND',
array(
'taxonomy' => 'product_cat',
'field' => 'slug',
'terms' => $category->slug,
),
array(
'taxonomy' => 'product_visibility',
'field' => 'name',
'terms' => 'exclude-from-catalog',
'operator' => 'NOT IN',
),
)
) );

foreach ( $all_ids as $id ) {
$product = wc_get_product( $id );
if ( $product->is_type( 'simple' ) ) {
$min = $product->get_price() < $min ? $product->get_price() : $min;
$max = $product->get_price() > $max ? $product->get_price() : $max;
} elseif ( $product->is_type( 'variable' ) ) {
$prices = $product->get_variation_prices();
$min = current( $prices['price'] ) < $min ? current( $prices['price'] ) : $min;
$max = end( $prices['price'] ) > $max ? end( $prices['price'] ) : $max;
} 
}

return ' (' . wc_format_price_range( $min, $max ) . ')';
}