I’m just an amateur, but I’ll bite. I apologize in advance for answering with more questions.

My initial thought was that any intrinsic value is going to be purely in relation to human consideration, and thus arbitrary, but on further consideration, I came to question the validity of that. Even without an understanding of the concept, could other living things not have a vague sense of value as well?

If so, I think we could possibly tease out some sort of basic intrinsic value that is at least common to most animals: companionship, comfort, sensory experience, escaping violence etc. That seems like a good starting place to me.

That would seem to fit into a fairly hedonistic world view, however, which seems to raise the question, are higher order conceptions of intrinsic value uniquely human? If so, does that make them any “less real”? I think this line of thought leads to your idea that intrinsic value is an illusion. I think this would fall under nihilistic or at least skeptical schools of thought.

But now what if you go the other way? Are our most basic hedonistic intrinsic values not just a consequence of our nature as progenitors of evolution? This seems to also lead to intrinsic value being illusory.