RouteSubscriber.php

<?php

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

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

/**
 * Alter the 'user.pass.http' route.
 */
class RouteSubscriber extends RouteSubscriberBase {
    
    /**
     * {@inheritdoc}
     */
    protected function alterRoutes(RouteCollection $collection) : void {
        if ($route = $collection->get('user.pass.http')) {
            $route->setRequirements([]);
            $route->setRequirement('_access', 'FALSE');
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() : array {
        $events = parent::getSubscribedEvents();
        // Ensure this event is triggered before
        // \Drupal\serialization\EventSubscriber\UserRouteAlterSubscriber.
        $events[RoutingEvents::ALTER] = [
            'onAlterRoutes',
            1,
        ];
        return $events;
    }

}