[CamperBob2]

If you simply copy the state of a brain along with the sensory information that yields a given set of state transitions, then of course, it's not exhibiting sentience. Sentient intelligence is the ability to react appropriately to novel input, which these models absolutely do.

The intelligence, such as it is, resides on the side that processes and understands the human's input, not in the output text that gets all the press coverage. You cannot get results like those discussed here from the operator of a Chinese room.

Now, if you take your deterministic brain-state model and feed it novel input, it will indeed exhibit sentience. To argue otherwise will require religious justification that's off-topic here. Either that, or you'll have to resort to Penrose's notion of brain-as-quantum-computer.