I am sincerely thankful for your intense interest.

You're right. We can throw out the notion of 'managing' the economy to achieve desired levels of (un)employment and/or inflation. As a profession, macroeconomics would go away, but microeconomics would still be with us. To your question at the end, if you limit it to "model" and "QE," the simple answer is, "Yes." (DDI is more than a "policy;" QE is simpler than MMT.)

One important point is that with a DDI (and including the option of funding government) there is a definite limit on how much money (as currency) would be created each year--though even without that option for funding government the amount created would be vast compared with the current paradigm. Basically, the economy would be flooded with money; to prevent inflation there would be a mechanism for catching overflows of money (accumulated, in practice, by large corporations--after all costs, including all remuneration of employees, had been paid) and returning it to its point of origin. [Large corporations would be the only entities that could accumulate enough money to create an 'overflow'.]

Another important point is that government would not be creating the money. That would be done either by the central bank or (my preference) by a newly created Monetary Agency

that would be separate from both government and the banking system. I that scenario in the U.S. the Social Security Agency could be extracted from government to become that Agency.