I've got a client using LearnDash, BuddyBoss, WPML, ACF and Woo for their subscription platform. It's dog-slow on the uncached pages, even on a very beefy serve

I've got a client using LearnDash, BuddyBoss, WPML, ACF and Woo for their subscription platform. It's dog-slow on the uncached pages, even on a very beefy server with only 5 concurrent users, choking the database apparently. Serving only 2 countries so don't need a CDN per se. (Why) Would this be faster on wp.com?