Ah morally that's correct. But in general, such thinking is giving up too much.
Capital T Truth exists irrespective of humans, no? For instance, Quantum Mechanics was True before it was discovered, and would have remained True whether or not there were ever any humans to investigate it. The same for whatever base reality is.
> The experience of my own existence - and the assumed irrefutability of it - is based on features beyond my control. How do I make my heart beat?
The way we experience it, sure. The fact that we experience something, be it a true reality or an illusion in a matrix, is irrefutable. That's exactly "what cogito, ergo sum" [0] is talking about. In fact, thinking along these lines is what led Descartes to come up with this principle. In a world of uncertainty where we cannot even trust our own senses, how can we arrive at any Truth? And he realized: everything else we think and experience could be false, but the fact that I am something that is able to think and exist is itself a truth that no one can take away! It's history is pretty interesting.