I think we generally agree with each other. The existence of an omniscient AI or deity doesn’t change the “experience” of free will. It doesn’t “invalidate choice” from the point of view of the observed. It does “invalidate choice” from the point of view of the observer, who can now say “This thing exhibits no unpredictable behavior to me”. You and I both think we have free will, because we can’t predict our own behavior. Our experience is unchanged, whether or not some other observer exists or could exist that could predict our behavior.

Agreeing on a frame of reference is exactly my point. “Does something have free will?” requires the follow-up question, “According to whom?”. Just like “I’m far from that rock” requires the followup question, “According to whom?”. The ant might think you’re far from the rock, something else might think you’re near the rock.

To boil it down a bit more, my point is just that you can always replace the phrase “free will” in speech with “unpredictable behavior” without loss of meaning, because that is what people actually mean when they say it, whether they realize that or not.