Are people still debating this? Here's my contribution: even if you believe substrate independence, you can still argue LLMs cannot be conscious. How?
1. Seizures change the discrete firing timings of neurons in the short term.
2. Seizures can effect consciousness.
3. Therefore, short-term discrete firing timings are important for consciousness.
4. LLMs cannot model short-term discrete firing timings.
5. Ergo, LLMs are missing a key ingredient of consciousness.
That's just a summary, the full argument is at the end of this blog post:
https://freethoughtblogs.com/reprobate/2025/12/26/llms-creativity-free-will-and-cognition/
Alas, I have yet to hear a good counter-argument to it. Maybe some day...