Storing an entity's UUID in an item?

Hi, this is a complicated issue but I want to store an entity's UUID in an item's tags.I've tried something that looks a little like this (I don't have Minecraft open right now, so forgive any inaccuracies in the syntax, this is purely for illustrative exampling):
/give @s book{UUID:[I;0,0,0,0]}
/data modify entity @s SelectedItem.tags.UUID set from entity  UUID
However, this and several other variants always return an error, either stating that it was "expecting an object but got  instead" or "unable to modify player's data".
Even when doing a similar thing but to a dropped item, it said that the data was successfully modified, but when I checked it, there was no change.
How can I do this? Is it even possible?