You asked me to document a controversy.

True, I accept that. The reason I said that is not a good sign is because it indicates he has an axe to grind and might be more interested in proving his point than in figuring out what actually happened.

On the basis of a brief look at your links, it seems to me that the controversy is really about, ahem, status of different historical periods. The people you quote think that Renaissance is overvalued, overexposed, overestimated, etc. while the late Medieval period is ignored and vilified. That might well be so, I have no opinion on the topic, but it's rather peripheral to your main topic of technological stagnation.

But I claim that there is substantial disagreement.

I suspect that a large part of that disagreement concerns what people are looking at. Once you give hard-edged definitions to the metrics you're interested in, much of it will go away. But if everyone is handwaving and implicitly or explicitly defining things in the way most advantageous to them, there could be much ado about nothing.