I'd flag the word "ultimately" in your sentence "But this does seem to give weight to the notion that even conscious deliberation is not ultimately free." The search for "ultimate freedom," like the search for "ultimate purpose," is doomed to fail, but only because the search itself is incoherent and hence ill-conceived. As you point out, ultimate freedom would require completing an infinite regress there's no reason to think we could complete. In that case, there's good reason to doubt that "ultimacy" is essential to the concept of freedom we ordinarily use and view as important especially in moral contexts. You summed it up nicely: "So you're free, but you don't have the impossibly infinite consciousnesses necessary to be ultimately free, right?" Right. Or at least the impossibility of ultimate freedom doesn't cast doubt on the possibility of freedom, just as the impossibility of an ultimate prime number doesn't cast doubt on the possibility of prime numbers.

Let me recommend (again) this book; the chapters in it authored by Robert Kane strongly emphasize the importance of ultimate responsibility (wrongly, in my opinion).

I recommend the essays in Part Three ("Questioning the Question") of E.D. Klemke's collection The Meaning of Life (Second Edition). If I may also mention my own short article on one aspect of this topic, you can find it at this link.

The literature on whether philosophical questions in general rest on false presuppositions is enormous. You might start with this SEP article (especially section 4.1). There's also a growing literature on whether metaphysics in particular (and ontology more particularly) concerns mostly pseudo-questions; see, for example, this collection.

I don't see how materialism as such bears on the existence of intrinsic value. The issue of whether anything has intrinsic value, and if so which things have it, seems independent of whether the world contains any immaterial substances (such as immaterial minds or souls). I think of values as abstract objects (non-physical non-substances), so if there are no abstract objects then there are no values, but there can be abstract objects without immaterial substances.

You're right that we haven't yet found a satisfying explanation of conscious experience in wholly materialistic terms, but even if we never find such an explanation, our failure to explain something wouldn't imply the logical or ontological claim that materialism is incompatible with intrinsic value.

You suggest that "conscious experiences, in general, have intrinsic value," at least from the first-person perspective. I'm not sure what the qualifier "in general" is doing in that clause, since the intrinsic value of something doesn't depend on all else being equal: whatever has intrinsic value has it regardless of how things are in the rest of the world, although its intrinsic value might be swamped by extrinsic disvalue. Maybe knowledge, as such, has intrinsic value, but someone can put his knowledge to horrific use, in which case it would be better overall if he lacked that knowledge.

I'd also question the idea that experience as such is a good candidate for something having intrinsic value: it seems to me that the value of an experience depends entirely on the quality of the experience and what it produces. There's net disvalue in experiencing only pain for the last hour of one's life, followed by permanent oblivion, even though it's experience. Are you perhaps saying, instead, that pleasurable experience has intrinsic value and painful experience has intrinsic disvalue, as classical utilitarians say? If so, then the intrinsic value doesn't attach to experience as such but to its character. Some utilitarians say that we can found morality on this basis. More on that at this link.