That termination threat is to me a signal that the company hates me and the business relationship is unrecoverable. I'd be polishing my CV and would be gone within a month of finding a better opportunity. Likely with a raise while I was at it.

Toxic environments like that are not worth working in. All sorts of other "interesting" corporate cultural aspects are usually also present. Their ethics are compromised so fraud and other criminal activity etc is probably going on as well. Even if not, the company is badly run and long term will fail in various ways for foolish reasons.