RouteSubscriber.php

<?php

declare (strict_types=1);
namespace Drupal\workspaces_ui\Routing;

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

/**
 * Subscriber for Workspaces routes.
 */
class RouteSubscriber extends RouteSubscriberBase {
    
    /**
     * {@inheritdoc}
     */
    protected function alterRoutes(RouteCollection $collection) : void {
        // Re-enable access to the workspace routes.
        $workspaces_routes = [
            'entity.workspace.collection',
            'entity.workspace.activate_form',
            'entity.workspace.publish_form',
            'entity.workspace.merge_form',
            'workspaces.switch_to_live',
        ];
        foreach ($workspaces_routes as $workspace_route) {
            if ($route = $collection->get($workspace_route)) {
                $requirements = $route->getRequirements();
                unset($requirements['_access']);
                $route->setRequirements($requirements);
            }
        }
    }

}