Notaro likely didn't have a contract at all for Discovery, but I doubt that would have affected anything. I don't get the impression that Wiseman would be overly expensive, either - Notaro is still the bigger star.
Maybe Wiseman just didn't want to commit to a full season or something.
From the trailer, I don't get the impression that they're trying to come back from it - rather, they're leaning in to it.