By default you get the following page template suggestions for a Commerce product:
page--product--[ID].html.twig
page--product--%.html.twig
page--product.html.twig
page.html.twig
Here's a template suggestion for custom page templates per product type:
/**
  * Add page templates for Commerce product types
  * Example: page--product--event.html.twig
  */
/**
 * Implements hook_theme_suggestions_page_alter().
 */
function THEMENAME_theme_suggestions_page_alter(array &$suggestions, array $variables) {
  if ($product = \Drupal::routeMatch()->getParameter('commerce_product')) {
    $suggestions[] = 'page__product__' . $product->bundle();
  }
}