transfer UVs via geometry nodes

At least a few of the geometry nodes manage to trash the UV mapping on an object (Join Geometry for one).

It would be super useful to be able to transfer the original UV's (or any UV's) back to the object after such an operation.

I know this is similar to another request to manipulate UV's for generated geometry, so apologies if I should have just upvoted that comment (and let me know and I can delete this). But this seemed different enough that I thought it might warrant its own suggestion.