Does it exist a schematic diagram of the quantum circuit implementing the symmetric UQCM $N \to M$ for unknown states? If yes, does anyone know a Qiskit implementation of it?
I have just found a paper which provides a circuit for the copying.
As far as I am aware, there is not a circuit level description for $N \to M$ quantum cloning, of any type (e.g. universal, state dependent, etc).
However, here are three papers (paper 1, paper 2, paper 3) which describe $1 \to M$ quantum telecloning circuits that are universal and symmetric. Quantum telecloning circuits require feed-forward operations. However, quantum telecloning has the same properties as quantum cloning with respect to the quality of the clone qubits and the properties of the clones.