This is the most plausible way of obtaining a full connectome looking from 2020 forward. Then you'd observe the slices with an electron microscope + appropriate Staining. Superintelligence by Nick Bostrom (2014) really opened Ciro Santilli's eyes to this possibility.
Once this is done for a human, it will be one of the greatest milestone of humanities, coparable perhaps to the Human Genome Project. BUt of course, privacy issues are incrediby pressing in this case, even more than in the human genome project, as we would essentially be able to read the brain of the person after their death.
As of 2022, the Drosophila connectome had been almost fully extracted.
This is also a possible path towards post-mortem brain reading.
The premise that "we can't make AGI, but we know enough about the human brain to upload on to a computer" is flawed. Edit: after reading Superintelligence by Nick Bostrom (2014), Ciro Santilli was convinced otherwise. What is flawed is of course just the "extracting connectome with macroscopic probes part". A post mortem connectome extraction with microtome is much more believable. But of course they weren't going to show fake slices of Jonny Depp's brain, are they? Famous actor bodies are sacred! What a huge lost opportunity. On the other hand however, the scale of the first connectome extraction would be arguably too huge to be undertaken by a random pair of rogue researchers. The same would also likely apply to any first time human brain connectome. It would much more likely be a huge public effort, much like the Human Genome Project.
But this film does have the merit of exploring how an AGI might act to take over the AGI might act to take over the world once created, notably by creating its own physical research laboratory. Though it doesn't feel likely that it could go under the radar for 2 years given the energetic requirements of the research. Even the terrorists find it before the FBI!
I also wish they had shown the dildo (or more likely, direct stimulation!) computerized Jonny Depp used to use with his wife before he managed to re-synthesized his body. But you know, 18+ would cut too much profits. Ah, what a shame.