Chalmers used them as a thought experiment to argue against physicalism and never believed them to be real.

Similarly, if consciousness is something that neurons do, simulating them through floating point numbers on a computer should also bring it about. I think dismissing LLM consciousness because they're parameterised through floating point numbers is only possible if one hasn't thought it through long enough. Other arguments are much more reasonable / harder to object to.

Yes I roughly think the same. Brains are physical systems, as of yet we don't know anything beyond turing computability or physics in them, neural nets further are modeled close to neural structure, further complicating the matter. Under present knowledge, I think the existence of other conscious entities is quite possible because well we ourselves exist and are a physical system, I follow a form of Pascal's wager here. I see no cost to myself in not mistreating current AI's personally.

But if simulated neurons can create consciousness, there's no guarantee of what level of detail that simulation has to operate at in order to produce that effect.

For instance, it's (unlikely, but) theoretically possible that it would require simulating them down to the level of subatomic particles, with perfect accuracy.

Right now, we're simulating them at a much, much higher and more abstract level, and AFAIK we barely even have the processing power to do that for the time being. So an artificial consciousness from simulated neurons may (again, assuming it's possible—which is a decent assumption, but not a certainty) take decades or even more for us to be able to achieve.