The Sculpt and Kensington expert trackball (big trackball, not thumb trackball), while not fixing my issues completely, did improve things for me quite a bit.

The Sculpt and Kensington expert trackball (big trackball, not thumb trackball), while not fixing my issues completely, did improve things for me quite a bit. That said, barring genetic lottery, as the sibling said: enough 15 hour sessions are going to give you RSI no matter what you’re typing on. There’s no way to do that every day, and exercise, take breaks, and sleep enough. Balance is important.