Copy/pasting cloth configs used to be possible in 4.23. It then got broken in 4.24 (crash) with the introduction of changes required for the new physics engine.
In 4.25, the config evolved to a Map container which doesn't allow the Paste command anymore, preventing the crash, but not solving the lack of copy/paste issue.
Result: The menu entry Paste is disabled.
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-92377 in the post.