So, for RSI, I have an alternative hypothesis. My issues are only with my right hand. I'm pretty sure the problem is not QWERTY, it's just the ]'/ keys. Having that one extra column of keys to reach across in order to get to the enter and shift keys means my right hand experiences a lot more wrist movement and stretching than my left hand does.
(I find hitting the enter key on an ANSI keyboard to be irritating enough that I'm frankly impressed that anyone tolerates ISO keyboards.)
I'm currently giving an ultra-minimalist keyboard, the Atreus, a shot. I'm still in the adjustment period, but it seems to be promising, and a much smaller adjustment than abandoning QWERTY entirely. Bonus points for not being the size of an aircraft carrier, like most ergo keyboards are.
It might depend on the specific problem a person has. I've never had discomfort with the actual letter keys on QWERTY, and definitely don't feel like I'm having to "reach" to get them. Where, to me, "reach" implies anything that's outside the comfortable range of motion.
For example, on a standard QWERTY keyboard, I find the number keys, the Y key, and the brackets to be a reach. Dvorak actually makes that situation a bit worse for me. It moves a somewhat more frequent letter, F, into the Y key's position, and it moves the brackets further away in order to put keys that I use less often in a more accessible position.
But that's me. I'd guess that this sort of thing varies a lot from person to person, because we all have different hands.
I get great mileage out of the Apple keyboard+number pad. Low profile, short, low-resistance key travel, great key density/spacing for my hands at least. It's a lot to like for a low-impact typist.
If it's only a physical thing for you, you might give the orthogonals a try.
That's where I want to "go next", but I've not yet seen anything on the market equivalent to the average Kinesis (solid, programmable, not horribly expensive, not requiring soldering).
The Keyboardio version of the Atreus is somewhat along those lines. It's very minimalist (44 keys, which is two more than the kit version), but it's well built, has staggered columnar key layout, and is very programmable.
The Mitosis that CarVac mentioned is another interesting option along similar lines, though I can't personally vouch for it.
(I find hitting the enter key on an ANSI keyboard to be irritating enough that I'm frankly impressed that anyone tolerates ISO keyboards.)
I'm currently giving an ultra-minimalist keyboard, the Atreus, a shot. I'm still in the adjustment period, but it seems to be promising, and a much smaller adjustment than abandoning QWERTY entirely. Bonus points for not being the size of an aircraft carrier, like most ergo keyboards are.