Bulk update product categories

add_action( 'admin_notices', function() {

	// Get Product Categories
	$args = [
		'orderby' => 'name',
		'order' => 'asc',
		'hide_empty' => true,
	];
	$product_categories = get_terms( 'product_cat', $args );

	// Loop Product Categories
	foreach( $product_categories as $term ) {

		// Get Meta Value
		$meta_value = get_term_meta(
			$term->term_id, 'meta_key_here', true
		);

		// Update Meta Value
		if( ! $meta_value ) {
			update_term_meta(
				$term->term_id,
				'meta_key_here',
				'meta_value_here'
			);
		}

		// Ticker
		echo '.';

	}

} );