In case this is helpful for someone else:

I had RSI for years as well, ended up changing careers away from tech for many years because of it. For an unrelated issue I started taking probiotics and gradually noticed the RSI had improved. It took a while to realize it was the probiotics doing it because I had generally been avoiding doing things that triggered the RSI. After I noticed I could type regularly again though, I've had a couple of instances where the RSI flared up again when I had stopped taking the probiotics for a week or two - that's when I finally realized that was likely the change that made the difference.

Looking back I had had the onset of significant chronic digestive issues a month or two before the RSI started and I know believe that was not a coincidence.