Hi, if I remember correctly the mesh that gets exported is gonna be different from the mannequin in unreal, I think I messed up the import at the time, or maybe it’s the control bones that get in the way, so you’d need to retarget unfortunately.
For future reference to import skeletal meshes into blender you need a world scale in blender of 0.01 and import the mesh with the default settings.
When exporting you need to select the mesh (just 1 LOD per export) and the skeleton, then use export selection with “add leaf bones disabled”
I’ll see if I get time I might redo this with the UE5 mannequin someday, although now using control rig and sequencer is probably the preferred option for animating stuff