I'd argue that if such a multiplier exists, it's infinite - there are completely non-productive engineers in the world. And I don't just mean on the scale of a

I'd argue that if such a multiplier exists, it's infinite - there are completely non-productive engineers in the world. And I don't just mean on the scale of a day (we've all had those) - there's a reason FizzBuzz was a thing; there are people with no practical coding ability nonetheless interviewing for engineering jobs. Somewhere, one of them got hired. Somewhere, they were able to BS - or download already prepared software that did what they were supposed to code - and keep that job.