In this video, we’ll be covering how to add Kinematic Constraints to your Flesh Asset which tells the Deformable Solver which parts of your Flesh Asset you don’t want to simulate.
https://dev.epicgames.com/community/learning/tutorials/XvKKe/fortnite-fab-unreal-engine-5-8-chaos-flesh-and-soft-body-physics-part-3-kinematic-constraints-beginners-tutorial