I feel like this is directly addressed in the article, right? I think you are coming from the same direction, but Rovelli goes a bit further and says "how can we affirm that there is gonna be a knowledge gap when we just aren't at that level yet?". How can you say that we won't be able to describe, explain and predict your exact internal mental state from a brain scan?
To draw a parallel with physics, about which we as a society (and me as an individual) know a lot more, we are gonna define mathematical objects and laws whose behavior maps well to certain subsystems of the brain that we ourselves have defined. Physics had it easy in this sense: it turned out to be remarkably simple to describe the universe to a great degree of precision. Still, we all recognize that the physics mapping we have to this day isn't perfect; and it's even possible that it will never be perfect. It may be fundamentally impossible to reduce some systems to simpler mathematical objects which we can reason about. It does seem to be generally possible, however, to find a reasonable approximation. This again is what I think Rovelli's point is about: science is the process of finding a good approximation which has predictive power. And what is there in the brain that's fundamentally so different and that we're never gonna be able to explain? Why does everyone keep insisting that consciousness is special?
I do agree that that only when (if) we do get the accurate mathematical description, then we're gonna be able to properly discuss the hard problem. But my hunch is that once we do have all the tools it will just dissipate from scientific discussion, similarly to how the measurement problem in quantum mechanics is slowly undergoing the same transition from "this is a fundamental problem" to "we were just asking an invalid question due to misunderstanding and old ways of thinking". Obviously I have no proof of this beyond intuition, but I more or less agree with every sentence of this article, and that shapes my intuition.