Material, there’s probably a cool and efficient way of drawing it purely in material.
Wouldn’t the 2D widget be more useful, am I wrong?
Not wrong. But I’d personally gravitate towards Spline + Spline Mesh Component or a Niagara Ribbon. Both live in world space and may end up looking much better in this instance. Rotating widgets leads to ugly aliasing that only pushing through a retainer box can make look half decent.
But this is an artistic choice that is, ultimately, up to you.
And lastly, in the above example the math could be done in pure 2D - would be probably less finicky, but then you’d need to send a 3d vector to the physically simulated cube anyway. 