I developed RSI from typing up long equations and calculations in TeX on a German keyboard layout with Emacs. It was a nightmare.
I switched to Vim, and a Dvorak layout. I really like the feel of Dvorak - every time I have to type Qwerty for an extended amount of time, my hands get uncomfortable.
I also like modal editing. You cut down on the amount of key chords you need. I've since switched back to Emacs with Evil.
Another trick is to implement some break routine. A typing break of 30 seconds every five minutes may already be enough. There are many tools ta enforce these. I used the venerable Workrave, but it's ancient and has bad UX.
I actually still use the (admittedly awful) Emacs bindings. I have both ctrl and alt available as thumb keys on both sides (using a Kinesis Advantage). I also activate these modifiers using an opposite hand to avoid "chording". This was enough to fix my RSI and keep using the bindings I am familiar with.
The Emacs bindings are excellent. On a MacBook i have Option as Alt and Command (next to the space bar) mapped to Control. Very comfortable setup for Emacs with no weird external keyboard required nor any inefficient sideways pinky reaches.
The Emacs bindings were designed for ease of learning, not ergonomics. For example C-n and C-p for next/previous, stretches the hand and uses the weak pinky for the very commonly used cursor keys (Vim uses the home row). I do use these bindings myself, but I strongly disagree that they are ergonomic or "excellent" (!)
I switched to Vim, and a Dvorak layout. I really like the feel of Dvorak - every time I have to type Qwerty for an extended amount of time, my hands get uncomfortable.
I also like modal editing. You cut down on the amount of key chords you need. I've since switched back to Emacs with Evil.
Another trick is to implement some break routine. A typing break of 30 seconds every five minutes may already be enough. There are many tools ta enforce these. I used the venerable Workrave, but it's ancient and has bad UX.