This is a fairly unrefined version of a possible strategy.
- Save the target's 'Position' attribute, before..
- Splitting the target's edges and flattening its geometry to its own UV Map.
- Fire rays down from a sheet of wrapper geometry onto the flattened target
- Use 'Hit' to trim wrapper-sheet
- Pick up the pre-flattened target Position from the ray
- Warp the wrapper using that position
(This is the step I think you're looking for....)
- Thicken the wrapper by some scale of its original Z, along (the unflattened ) target's transferred Normal.
'Unrefined', because there's probably a nicer way of handling seams, reducing gaps. But this is maybe a start.
In response to commentary. The best luck I've had so far with a trim to cover seams, maintaining a half-decent topology, is to delete the original mesh where it is not close to UV seams, and extrude the rest:
With this sort of result.. it's pretty twitchy, but with careful attention to bevelling the original, seam placement, and scaling UV islands, could be OK: