Get attribute from slug and output in ACF field
$term = $product->get_attribute( 'pa_slug' );
$term = get_term_by('slug', $term, 'pa_slug');
$output_acf_field = get_field('output-attribute', 'pa_slug_'.$term->term_id);
$term = $product->get_attribute( 'pa_slug' );
$term = get_term_by('slug', $term, 'pa_slug');
$output_acf_field = get_field('output-attribute', 'pa_slug_'.$term->term_id);