You can use a throw away key for that.
Public means anyone can read it
Private only you can read it
You own both though and can change anything.
Private shares (not till after release) have shared ownership and these are contained within a group with decrypt keys. Group removal of a user means re-encrypt of all data with a new key.
A neat trick you can do is, copy the datamap (not the data chunks) and keep that published youself. It’s signed by the original owner and the data chunks are immutable. So you can copy whole sites for a single datamap. So record 10 sites for the price of a chunk.
This is another way to make public recorded info immutable and last forever. I have not detailed it yet, but you can see how simple this can be.