I don't think that is true. If you have a good understanding of disease and treatments, a lot of the time you will be able to provide very useful help without knowing for sure exactly what the patient 'needs from their perspective and in their terms'. The proof of that is that doctors in an Emergency Room can often provide substantial help to an unconscious patient who is unable to inform their medical team of their perspective.
Frankly, give me any day competent ethical 'biological reductionism' and 'chauvinism derived from [an accurate understanding of the] relationship between pathogenic causes to symptoms' over an incompetent doctor who wants to spend time trying to understand what I need from my perspective and in my terms.
That's definitely true, but it only applies to issues where that biology is known. All medical gaslighting occurs when it's unknown, and it's a common thing. If it were rare things may work out on balance, but it's far from that. And in some ways the success of this approach is a major reason why there is no plan B, no one ever thought of having a plan B before precisely because it's not needed in all the cases where it makes no difference.
But of course almost no one can actually do that reliably, but the problem is that a lot do seem to believe they not only can do that, but do so reliably. It all depends on what the words mean. For me it's strictly about symptoms, their patterns, differences, functional limitations, and so on. But somehow that's considered useless, largely because in cases where the biology is well-understood, none of this is actually needed.
I don't see how illnesses like ME/CFS get fully solved without that. Not our feelings, or beliefs, or what we think, or any of this psychosocial mumbo jumbo. That's entirely useless. I could not care less for someone to smile at me reassuringly, holding my hand telling me it's all going to be OK, especially when it's false, which is the case here. I would be perfectly fine with a disembodied AI doing the whole work without ever faking any of this.
But to solve illnesses where the biology is unknown does require working with the patients and our perspective. It's just that this means none of the usual biopsychosocial/psychosomatic garbage, but rather a whole different branch of medicine that doesn't even exist, and would have meaningful, reliable, accurate and replicable skills doing that. Something that has never been done before, and therefore means no one can teach it, while it appears that millions of physicians believe they already have those skills, and would gladly teach their peers wrong about it.
So it's definitely true that our perspective is critical. When we compare what patients bring unprompted about what needs to be done, it's massively superior to what medical professionals bring when they do the same exercise, or when they work in highly-prompted discussions where they inject their own priorities and pass them as the patients'. They are literally worlds apart. On one side everything that needs to be done to solve this, research, expertise, and so on, and on the other is the multidisciplinary fake-sincerity psychosocial garbage that has zero chance of ever achieving anything.
The problem is always with the professionals. They don't just bring nothing here, they make everything worse because they can't help inject their own perspectives, which is only valid and useful when it involves biology and physiology, as they are trained to do. Just the same when it comes to medical gaslighting, the problem is explicitly that the professionals are wrong, a perspective that they can't even imagine.
Biopsychosocial/psychosomatic is plan F, failure by design. That doesn't change that there is a need for a real plan B that involves working with patients, as opposed to working the patients, because medicine is still very far from knowing half of everything there is to know. Having ruined everything by working with a failing approach doesn't change that, and that it absolutely requires working with the patients and our perspectives, it just has to be completely different from everything that's been done, all the way down to the motivations and intentions. Good intentions don't count when they have zero chance of achieving what they set out to do.