There are probably multiple different causes for RSI in programmers, but for me, a regular keyboard is fine. Even my slouch is fine. I type with my elbows on the table and it's fine.
It's the mouse that killed me. A handful of years after graduating from college, I thought my programming career was over because the pain in my neck and shoulders was so bad I couldn't type. I went to a bunch of doctors, neurologists, physiotherapy, etc but nothing helped, not even medication.
It turns out twisting my right hand outward in order to accommodate my mouse to the right of my keyboard was the culprit. I changed my entire set up so that my mouse is away from my keyboard when I type, and when I need to use the mouse, I push my keyboard away and have the mouse on the table in the center of my body, with my wrist slightly twisted so that it mimics writing with a pencil. That's also why Macbooks and similar laptops are fine with my because it's in the middle.
Once I switched to this technique, my carpal tunnel went away. It's been over 25 years now with no pain. Like I said, different people probably have different causes of carpal tunnel, but for me this was the precise reason.