I've seen it with people religiously sticking to an optimal typing method which limits their hand movement to an extreme. They were crazy fast but RSI was a common subject of discussion, regardless of posture or hardware quality.
We had the same issue with gaming controllers, some with guitar learning etc. There's a limit on how much we're able to repeat the same movement again and again, it depended on what movement and who did it, but the only ones who didn't get any RSI simply avoided extreme repetitions.
And buffs. Sometimes building more and more muscles solve the issues entirely, if that's what you're into.
I solved it in a couple of ways:
1. Quit wow
2. Rock climbing. Get stronger, especially forearm and finger strength. I can't emphasize enough how much this helps over even carpal tunnel braces or whatever. The biggest single thing that stopped wrist pain.
This definitely does not describe me. I typed around 100wpm, sometimes quite loud, often times quite a button mash, and frequently not lifting my fingers quickly after each press. Didn’t have any notion of “correct” typing
I did not "touch type" in the traditional sense of correct form and using the home row, but I didn't need to look at the keyboard. I typed around 120wpm like this though at the time. I have not and probably never will get back to this speed typing on the Kinesis. I'm closer to just 90-100wpm with stricter typing technique. But usually try not to type as fast as I can anymore anyway. I still to this day type faster with my crap form on a laptop keyboard if I swap to it for a bit even though I rarely do anymore.
My typing form was honestly atrocious. If I were to describe it I covered over wasd with my left hand as if I was gaming, and pinky was only ever really used for modifier keys and shifting. I only used left shift, never right. My right hand I used index finger for spacebar and moved my entire hand to the spacebar between every word. I didn't even realize I did this until I sat and analyzed my typing form maybe a year ago to compare to correct touch typing.
It actually took me quite a while to learn to type on a split keyboard since I basically had to learn to type correctly from scratch.