I would expect that SSDs do normally clone data internally when copying. Often when given a write operation by the OS the SSD would not be aware of where it alr

I would expect that SSDs do normally clone data internally when copying. Often when given a write operation by the OS the SSD would not be aware of where it already stores that data. Drive read and write performance is commonly benchmarked - I don't recall seeing copy performance tested as a different category which would have much different results if they automatically 'deduplicated' files. I believe SSDs are COW in the respect that they cannot make partial changes to a page so need to write a whole new page at a time, but not that the drives can arrange multiple file handles to point to the same data. That should be a responsibility of the filesystem.