Earlier quoted context omitted.
I'm not a physicist; but the GP mentioned consciousness as an alternative to matter as the fundamental "substance". Well, I've come across that idea before; in certain kinds of Buddhism, consciousness is considered fundamental, the senses are created by consciousness, and the material world is projected by consciousness through the senses. Well, this was explained to me in the context of a particular type of tantric…
...so you're just using "Brahma" to refer to the computer that is running the simulation that is the universe. And when the simulation becomes aware of its own condition, it becomes conscious? This is just rephrasing of the symulation hypothesis in mystical terms and is just as useless as the symulation hypothesis itself (regardless if it's "true" or not). There's some valuable deeper stuff in hindu and buddhist phil…
That "Brahma" isn't a computer; the model doesn't suggest that the universe is a simulation. You seem to have wedged in an interpretation that is fundamentally materialist, which sort of misses the point; according to this model, consciousness is fundamental. That is what was being discussed.
I agree that it's "mystical" to postulate that consciousness is fundamental; but it's equally mystical to assume that matter is fundamental.
In the Buddhist tradition where I learned this, the Brahma story was just that - a myth. But they treated the "consciousness is fundamental" thing as a core teaching, they elaborated it, and the practices grew out of that view. The tradition was a practice tradition; they shunned metaphysical speculation, and "philosophy" was generally treated as another technique for breaking-down conceptual thought.
This wasn't something you were supposed to believe, or reason about; it was presented as a way of seeing the world (a "view") that was useful in Buddhist practice. In the same tradition, we were taught that all views are provisional.
I was just answering the OP's question about what "fundamental" means in this context. I am not advocating for the view that consciousness is fundamental. I happen to take the view that consciousness exists, and is not an emergent phenomenon; but I don't have a philosophical system built around that idea. It's just that I can't see how the subjective experience of consciousness can emerge from what amounts to a system of levers and gears.