For now, entity bundle classes generated by DCG 2 are placed in the namespace Drupal\mymodule\Entity\Bundle:

<?php

namespace Drupal\mymodule\Entity\Bundle;

use Drupal\node\Entity\Node;

/**
 * A bundle class for node entities.
 */
class ArticleBundle extends Node {
...
}

However, most documentation and blog posts I've seen for now favor putting them directly in the 'Entity' namespace. Here's an excellent example: https://www.hashbangcode.com/article/drupal-9-entity-bundle-classes.

This is highly opinionated, but IMHO DCG should follow established best practices, so I'd suggest changing the namespace.