When importing a metarig from Blender, the resulting skeleton asset has bones scaled to x100 the normal size. I understand this is because the default distance unit in Blender is meter, while UE has centimeters, but following the few forum posts that claim to have fixed this (set Blender scene to centimeters and the scale to 0.01) only results in getting microscopic assets, while the bones remain relatively x100 size, compared to the Skeletal Mesh.
