Help user see webform subbissions with per-webform access. See https://www.drupal.org/project/webform/issues/3196440

foo.services.yml

services:
  foo.route_subscriber:
    class: Drupal\foo\Routing\RouteSubscriber
    tags:
      - { name: event_subscriber }

FooAccess.php

<?php
// src/Access/FooAccess.php

namespace Drupal\foo\Access;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Entity\EntityInterface;
use Drupal\webform\Access\WebformEntityAccess;
use Drupal\webform\WebformInterface;

/**
 * Defines the custom access checking for webform operations.
 */
class FooAccess extends WebformEntityAccess {

  /**
   * Allow users to see the route if they are only allowed to view submissions for this specific webform.
   *
   * Note that "View any submission" is also required to see relevant webforms in the webform overview.
   *
   * @see https://www.drupal.org/project/webform/issues/3196440
   */
  public static function checkResultsAccess(WebformInterface $webform, EntityInterface $source_entity = NULL) {
    if ($webform->access('submission_update_any') || $webform->access('submission_view_any')) {
      return AccessResult::allowed();
    }
    return AccessResult::forbidden();
  }

}

RouteSubscriber

<?php
// src/Routing/RouteSubscriber.php

namespace Drupal\foo\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Drupal\Core\Routing\RoutingEvents;
use Symfony\Component\Routing\RouteCollection;

/**
 * Subscriber for webform routes.
 */
class RouteSubscriber extends RouteSubscriberBase {

  /**
   * {@inheritdoc}
   */
  protected function alterRoutes(RouteCollection $collection) {
    if ($route = $collection->get('entity.webform.results_submissions')) {
      $route->setRequirements(['_custom_access' => '\Drupal\foo\Access\FooAccess:checkResultsAccess']);
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    $events = parent::getSubscribedEvents();
    // Need to override the generic "view any submissions" permissions that is not explicitly defined by the webform.routing.yml
    $events[RoutingEvents::ALTER] = ['onAlterRoutes', -999];
    return $events;
  }

}