Hello Matthew. I fixed this issue in my custom Blender Next build for Unreal Engine. Via this custom build you can rig 3D characters on Unreal Engine 5 and 4 Epic Skeleton without any plugins. Just import FBX file from Unreal Blender and fit skeleton to your character. Here two tutorial videos from my YouTube channel:
Pose Mode armature display: Blender Next for Unreal Engine 5. Update 4. Pose Mode Symmetry - YouTube
Edit Mode: Blender Next. Update 2. Armature creation, display and tweaking tools for Unreal Engine 4 and 5. - YouTube