I have RSI issues with my wrists. It really helps to have split ortholinear keyboards, if only because I have trained on them specifically to type without moving my wrists whatsoever (using a miryoku layout), while old habits persist on a standard QWERTY TKL. Of course, it also helps to put on really soft-springed keys (like kailh silver) — it's self evident that softer keys are easier to press.

I had initially thought that it'd be hard to use both kinds of keyboards at once, but my muscle memory for either seems unaffected when I use the other one.