Haven’t you missed a 7th option in the workflow: something like “Mark as Spam” or some other title essentially meaning “Do what is needed to try to ensure we never receive such an email again”?
I know you preceded the workflow with an initial unsubscribe-fest, but these days that can’t mean we are clear forever. Try as we might, we’re always going to end up on someone or other’s mailing list every so often, even if it doesn’t meet the legal definition of spam. (I call such things Spam-ish — I don’t care what the law says, just because I buy something from an online vendor doesn’t mean I want on their list.) So surely we need a workflow option to handle such messages on a regular basis?