Why Hybrid in "Hybrid Mind Uploading"
As far as we know, consciousness has only ever shown up as an ongoing physical process in living tissue (unless you're willing to make some huge leaps about the nature of reality). That's where I'll start, and I'll try to assume as little as possible beyond it. It's also why I'm so fussy about the "hybrid" in the name. By hybrid mind uploading, I mean any route on which a living brain and an engineered substrate co-run and gradually integrate, until part of the person's phenomenal experience (maybe, eventually, all of it) is realised by the engineered substrate. That substrate can be biological, biohybrid, biomimetic or fully non-biological. Nothing gets scanned out along the way and re-instantiated somewhere else as its own free-standing "thing", disconnected from the brain that we're trying to "upload"/preserve.
Whether an engineered substrate can realise a mind is the hypothesis under test, not an axiom to build into the definition. The "uploading" part only tells you where you might end up => all the interesting questions live in the "hybrid". Philosophically, I'm going for maximum conservatism: whatever survival is, it can't be anything more abstract than the process itself, running on without interruption. Want to put it somewhere more abstract (a pattern, a program, a file of weights, etc.)? Fine, but then that extra step is yours to justify, and with someone's life hanging on it, you'd better have a pretty good argument!
"But an upload might be conscious. It might even be you" => sure, and we might all be living in a simulation, and the rest of you might be furniture in my dream. You can hang any story you like on a bare "might", however wild, so the most it can do is make you careful. The real worry about classical uploading (scan, store, simulate via software) is much more down to earth. Run a description of your functional organisation again somewhere else: does that actually continue your exact process, or does it just kick off a new one (or nothing at all)? For it to continue yours, there'd have to be some second thing (a soul, software, meta-reality => take your pick) that can be peeled off the process and set down somewhere else. Nobody has managed to show that there is such a thing. Classical mind uploading simply takes it for granted, and in doing so buys into a fairly Platonic picture of minds, one where they can exist apart from the biophysical reality that's carried every single one of them so far. And should that picture turn out to be wrong, we'd end up building an enormous graveyard of p-zombies (or, at best, of "strangers" with our memories).
Don't forget: done at scale, classical mind uploading might even be the Great Filter! So, start with the biology and build upwards from there (slower, probably harder, but a lot less likely to kill anyone) :-)
PS: The video is the idea at the cell scale: a neuron, a scaffold growing around it (i.e., hybrid state), and the de novo "neuron" (doing the same physics as the original neuron) that's left once the scaffold has taken over.