For me intelligence is a fairly clean-cut concept, and is somewhat inseparable from consciousness itself.

Briefly, any intelligent creature has internal stochastic processes like sensory inputs and feelings to a certain degree. These stochastic inputs and the creature's own actions change the creature in subtle or profound ways. An LLM has no such processes. You push inputs to the same static model, sans temperature which is just a randomness slider.

Considering the model even doesn't see the words and work on matrices of numbers is even more telling. One needs to add "tools" and other "experts" to overcome the shortcomings caused by this modus operandi.

I can call the algorithm/model smart as in a smartwatch. It can mimic certain things well while having none of the underlying foundation beneath it, or redirect some of the things to correct tools to get deterministic and accurate results if it can't evaluate the query inside its own network in a sane manner.

Coming to your question, "simulating a brain" in a static manner would not make that simulation intelligent, but if you can "wire" it completely and let it evolve by itself, now we're entering a territory I have not spent enough time for thinking it through.

Oh, as I said "I don't know", an LLM doesn't know what it doesn't know, and can't self correct itself which are required capabilities for understanding something. It just generates something statistically viable via its network.