- 🇺🇸United States rszrama
Generally speaking, it's not that Drupal Commerce can't support these sorts of setups, it's that it's never been particularly optimized for it. (As you can see, you have wildly different results as different types of users.) The work here would be to trace those queries, figure out what's slow, and either optimize or avoid them. I've done this before when dealing with massive taxonomies.
That said, there's not much for us to tease out here in the queue. If someone has a specific optimization, they're welcome to open an issue for that with a patch. We won't be taking on solving this ourselves absent some specific client obligation.