In the FIDO2 case, only the derived keys are extracted. The master key that derives non-resident keys isn't extracted. So I think it's not possible to really copy the key.

In the cases of FIDO2 resident keys (passkey) / PIV / GPG, maybe it's possible to extract and copy the exact keys. But I guess it can be detected through attestations.

And I just looked at ykman command. It doesn't seem to allow you to import a passkey to a Yubikey.