Caveat here that I have no specific expertise in this area.

As far as I'm aware, all of the current work on brain-computer interfaces are focused on output, interpreting electrical signals from the brain either to control external devices or perform some extremely simplistic form of "mind reading." I don't believe anyone is working on input.

That said, there is no reason in principle it can't be done, but there are additional challenges in that encoding knowledge in the brain involves changing neural architecture, and doing that via attached mechanical device is risky. The closest to this we've ever achieved is electroconvulsive shock therapy to try and treat certain types of psychiatric disorders, which is controversial at least. I have no idea how effective. We don't currently have the means to do this at any finer granularity level and we wouldn't know what we're doing anyway because we don't know in any general way how knowledge gets encoded in the brain (and for athletic activities like kung fu, the entire CNS, not just the brain).

I can imagine at least a line of research where we attach extremely good internal sensors to a person's entire CNS and observe what happens when they train. If it looks sufficiently similar on all test subjects, you can possibly assume what you're seeing is a pattern of electrical activity that amounts to "learning kung fu" and then try to induce that via mechanical device rather than actual training.

Even if this works, however, you're limited by a few factors. One, if you've ever done any serious athletic training, you'll know it can actually fry your CNS, not just cause muscle soreness. Your CNS does need time to recover from learning activity. So you can't just upload kung fu instantly, or in the span of hours like they do in the Matrix. The human CNS can't actually handle that level of continuous input and needs rest and recovery.

Let's grant you can still learn faster than by actually training. In The Matrix, they're only ever performing kung fu in a simulation, not in physical reality, so their level of physical fitness doesn't matter. Performing real kung fu takes more than just knowing kung fu. You need to be sufficiently physically fit, in terms of strength, endurance, aerobic capacity, flexibility, everything it takes.

I can imagine a future where, given these limitations, maybe time to mastery can be decreased from 20 years to 2 years, but I don't see it ever being possible to become a kung fu master in a matter of hours like in The Matrix. At least one major difference between brains and hard drives is brains can only have knowledge encoding gradually changed. We need repetition to learn. It isn't possible to just erase a file and write a new one. There are no files. And the rate at which it is possible to learn is inherently limited by biochemical realities. "Electrical signaling" in the brain involves ion channels opening and closing, physical molecules moving around. It's an energy consuming process and it wears down the cellular machinery that then needs to be repaired by producing and emplacing new proteins to replace broken down. These same things are true of silicon microchips, but there are major differences in that you can just keep it plugged in and give a continuing energy source. Humans need to eat, digest, excrete waste, all of which take longer. CPUs can be much more easily and quickly cooled. Some rigs just blast them with liquid nitrogen, which you definitely can't do to a brain. And they can be replaced. You don't need to rebuild them in-place at the molecular level. You can just keep a fresh stock of excess chips, and when one burns out, replace it. When a hard drive fails, you have backups of the file and write them to a fresh hard drive. You can't do that to a brain. You have to let it recover and rebuild itself in-place.