Developed RSI 15 years ago, tried all kinds of contraptions. Here's what helped me:

- Kinesis Advantage keyboard w/ footswitch https://kinesis-ergo.com/products/#keyboards

- Ambidextrous mousing (one on each side, to split the load). Favor your PageUp / PageDown buttons over the evil mousewheel.

- Lifestyle changes (biggest bang for the buck). Try to get at least 20 minutes of aerobic exercise in each day, e.g. running.

- Proper ergonomic positioning

This video from the article is a phenomenal demonstration of dictation coding: https://youtu.be/Mz3JeYfBTcY

Fun fact (or myth?): Your tongue is one of the few muscles in the body that can't get RSI. I played around prototyping a tongue-switch a while back using a flex sensor.