I understand the argument but I disagree and would phrase it the other way around. We don't have evidence of conscious experience because we don't have evidence for a division between conscious experience and "existence/physical stuff" in the first place. This division is created by our brains and the model we have of the world but in reality the only evidence we have is that something exists.

Therefore, what we call subjective experience is evidence for the existence of what we experience, but until we can empirically show that there is a difference between what we experience and what reality is, the only thing we can say is that it exists. Also, that's the problem with the hard problem of consciousness - it assumes a division between the two, and we have no evidence of such a division. And lastly if it's not clear i am not a panpsychist either because that assumes a division on some level again. We don't know what existence itself is and how it functions really, at least not the brains function within existence.