I significantly reduced the symptoms of my carpel tunnel by changing from a normal height mechanical keyboard to one with slim key caps. I really miss my Das Ultimate but the difference is really noticeable.
Now I use the very-average Microsoft Sculpt Ergonomic. Low keycaps, low travel. And of course a split layout.
Do not use the execrable MS mouse that comes with that keyboard. I love the MX Anywhere series, I currently use a 2 and a 3. They're light, so you can nudge them round with your fingers without having to move your arm too aggressively.
I find it really helps not having the number pad - it means my mouse can be closer to the keyboard so my wrists are straighter.
For a mouse I use a MX Master 3 which I'm very happy with.
I remember reading a Medium article a while ago about a software engineer who described how he addressed his "RSI", which I suspect was just TOS - he switched to an ergonomic keyboard and vertical mouse, which over a period of MANY MONTHS more or less resolved his RSI. He talked about how he still has to be careful and take breaks often. I really think, especially considering his age (20s), he could have kept the mouse and keyboard he had, if he just engaged in posture-correcting shoulder stretches and strength exercises.
The Anywhere is just smaller, lighter. More nimble.