Well put. I often make this argument. Just imagine all the hormones and processes that must happen outside the head just to keep you sane or at the very least conscious and remotely functional.

The brain upload hypothesis seems a bit naive. I could see a synthetic body hypothesis. Imagine if we could reproduce all these organs via some method and move the brain or the head to a new host. But turning this stuff into software? Very implausible

Longevity research is probably the way to go. I imagine that's the first baby step in creating synthetic hosts anyway.