SBF, I'm aware of (did you see what I just did there?) what panpsychists say. I don't require a restatement of what I already understand.
What I require is some evidence to support their assertions. As far as I have seen in the literature on the subject that I have reviewed and from any of the comments put forth here, there is none.
The definition(s) of awareness that you cite via Nagel are problematic. They are formulated as a question, the answers to which are by definition unknowable by us. How can anyone know what it's like to be a cat or a tree or an atom? We can't. We can't even know at what point the answer would be nothing. Hell, it's hard enough to know what it's like to be human! And my experience of being human is likely quite different than yours.
As a result, while these sorts of questions are seductive mind-candy for a parlor room game of wild-pseudo-philosophical speculation, they do not, indeed they cannot, move us toward a better understanding of the subject under discussion.