works for me on macOS 15.5 … using /usr/bin/tar
man tar also shows its available…
that said, in checking this I noticed it says you don’t need —zstd unless you are creating an archive (though it doesn’t mind having it) - since by default tar will detect it and decompress automatically.
I do have zstd installed via homebrew. and it is on my path, not sure if this is necessary or not, as above it seems part of macOS these days - that said, I have homebrew installed and setup on all my Macs.