Metahuman is great for fast creation of detailed characters, and even better for bringing those characters to life with Metahuman Animator. And yet, Metahumans are not automatically optimized for games. This tutorial walks you through common issues with creating lively dialogue-ready custom Metahumans, and it shows how to solve those issues.
https://dev.epicgames.com/community/learning/tutorials/LZ5o/build-an-unreal-engine-npc-using-metahuman