Control Rig based on simple Blender armature behaving oddly

Does anyone have experience using UE5 Control Rig with armatures made in Blender? I’m trying something very simple and having a weird problem as soon as I move beyond the most basic step: I’m trying to copy the FK robot arm from Control Rig | Unreal Engine Documentation , and putting the controller on the root bone works but the control for the first actual bone is (1) causing it to point backwards compared to where it should be (you can see it in the preview viewport on the left, that orange bone should be positioned under the arm base, not away from it), (2) not causing the bone / the mesh controlled by the bone to rotate at all, and (3) causing the end few bones of the arm and their child mesh parts to hover in space as though the arm were pointing the entirely other direction.

The skeletal mesh works fine in the viewer on its own, so my naive guess is that Control Rig doesn’t like Blender’s different-handedness-from-Unreal bone axes somehow?

Ok, 2/3 of my problem was I’d named the bones in blender using spaces in the names, and the skeletal mesh rig hierarchy put in hyphens but the control rig hierarchy put in underscores… so only the bones named “root” and “hand” were finding their counterparts.

Very odd, as the control rig hierarchy was created from the skeletal mesh, and anyway I would’ve expected the bones to all be renamed by Send2Unreal upon export from blender. Oh well, live and learn.