There's absolutely zero clinical/valid evidence that Cherry MX switches do a shred of anything for RSI.
It's all hype. There's nothing medical behind any of it.
I find the extra key travel of those switches fatigues my fingers/arms far more and makes me feel far more like I'm going to have RSI.
I did have full blown RSI, and ditching mechanical keyboards was a key part of getting past it. Now that's just my anecdote, there's no evidence the mechanical switches are actually worse. But there's no evidence they're better either.
No one knows whether it's hard rebound or key travel or anything that actually causes the issues. And different RSIs are totally different. It's possible Mechanical switches could be better for carpal tunnel but worse for tendinitis or vise versa. But it doesn't seem like it has been studied.
My experience with medical treatment was doctors and PTs don't even know what the different types of keyboard switches are at all. They know about desk positioning and ergonomic shaped keyboards but switch type was not something that they had any advice on.