"But the thing is, the exact same thing is true for your brain too!"
That is pure speculation. Just because we can observe similarities between two phenomenons it doesn't mean they are the same thing. You're erroneously assuming that the universe can only work in a way that fits our theories and models.
What are you suggesting? That the brain fundamentally is not a machine, a process of some kind? Even if everything we know about the universe was wrong, which could be true, but it is far, far, far from pure speculation. You might as well say it's pure speculation that gravity exists.
That is pure speculation. Just because we can observe similarities between two phenomenons it doesn't mean they are the same thing. You're erroneously assuming that the universe can only work in a way that fits our theories and models.