Not trying to argue at all, just spitballing off your thoughts: I feel like (assuming souls are things that exist) the brain is the hardware and the soul is the software in this scenario. If your computer’s mother board develops a problem, the data on your hard drive still exists and works; the hardware just can’t compute.
That all being said I’m an agnostic and I don’t really know the answer to OP’s question. I’ve kinda always assumed there was some star trekish we-are-just-energy thing going on. But I ultimately accept that we don’t know and can’t know and won’t know until we do.