I think you are seriously overestimating our current understanding of the universe/physics. For instance we don't even know if our universe is finite or not, if

I think you are seriously overestimating our current understanding of the universe/physics. For instance we don't even know if our universe is finite or not, if it's infinite then your point is moot and you literally would have access to infinite compute. I disagree, I have seen research indicating that it's reasonable to have a computing system with on the order of 10^69 bits. There doesn't seem to be anything magical about this thinking at all. https://arxiv.org/pdf/1705.03394.pdf https://arxiv.org/pdf/1705.03394.pdf