Sheet and plate development is widely useful for things as diverse as sailmaking and boatbuilding, ductwork, vehicle bodywork and other. Some CAD applications have specific tools to assist this, such as tools obviously labelled "ruled surface". TC has the tools, but in less-than-obvious locations.
TC creates ruled surfaces when you specify "TC surface" in 3D properties beforehand. When you've lofted the surface, explode it immediately from "loft" to "TC surface", then switch it back to "solid" in 3D properties. Your surface is all triangles.
In the first picture, I've lofted two 3D splines and switched them in that way.
In the second, I've placed spheres to subtract at triangle apex intersections. The reason for that is that if an intersection has more than two faces adjoining a vertex, unfolding will fail. After the subtraction, fillet the edges with adjoining faces as shown, then shell the surface.
The small inset showing the unbending having happened from both sides. That's not always so. Sometimes if you select a face, TC will have a think about it then return "can't unbend object". It's worth trying it from both sides, because you'll often notice that unfold face will work on a cone or cylinder, but if the object is shelled, not on the opposite side of the shell, which should also, in theory, be a conical or cylindrical surface. Unbending also seems to be sensitive to that effect.
In the third picture, the edges are restored with facet edit. The cutouts that resulted from the spheres have their facets highlit and deleted, which restores the complete edges so you can trace the outline of the sheet to cut.