Hey, neuroscientist here. Just FYI, Neuralink is doing some good stuff around implantation surgeries, but that's really about it. They haven't solved the main issue of glial scarring or how to feed information into tissue long term (at least as far as I know).
As far as the neuroscience field is concerned, no-one is able to solve those issues, and we're ~60% sure you can't solve them, ever. My crazy pet theory is to use optogenetics (stimulate with light, not electrodes) and some multipole magnets for nerve shaping. But, that is a legit crazy theory.
Point is, good people, good work, very crazy boss, very unlikely to make stated goal ever.
It was about the sheer intractability of trying to upgrade extremely legacy wetware signaling at 100m/s to a level anywhere near the speed of light which modern inorganic stuff operates at. Even if we manage to solve the incredibly hard physical problems you mention, the mismatch on the signaling level is still 6 orders of magnitude. Compared to that challenge digitally recreating an entire human brain is almost trivial. Digitally creating something similarly potent is far easier still.
People use those images of the future as proof that we can't reliably predict it, but a lot of them were made by people who didn't understand physics, psychology, economics, etc. very well or just didn't care; they were just making a pretty, evocative picture. The reality however is that we can predict and have predicted aspects of many things based on what the limits of this universe are.
I would argue for instance that the speed of light being a maximum is directly responsible for the convergent (biological) evolution of eyes.
It's like imagining flying horses (and flying cars, for that matter).