Filtering according to the locale ‘de_DE’

To achieve filtering according to the locale de_DE for the taxonomy terms displayed in the search box selector, you can use a similar approach as your archive title filter.

add_filter('wp_dropdown_categories', function( $output, $args ) {
    $locale = get_locale();
    if ('de_DE' == $locale && $args['taxonomy'] == 'tipologia') {
        // Modify output for German locale and 'tipologia' taxonomy
        $terms = get_terms([
            'taxonomy' => 'tipologia',
            'hide_empty' => false,
        ]);

        if ($terms && !is_wp_error($terms)) {
            $output="<select name="" . esc_attr($args['name']) . '">' . "\n";
            $output .= '<option value="0">' . esc_html__('Typology', 'sacconicase') . '</option>' . "\n";
            foreach ($terms as $term) {
                $output .= '<option value="' . esc_attr($term->slug) . '">' . esc_html($term->name) . '</option>' . "\n";
            }
            $output .= '</select>' . "\n";
        }
    }

    return $output;
}, 10, 2);