Not sure exactly how bad "severe" is, but I had a lot of luck with my RSI switching to two-fingered typing for a (long) while. It's crucial to keep everything

Not sure exactly how bad "severe" is, but I had a lot of luck with my RSI switching to two-fingered typing for a (long) while. It's crucial to keep everything below your elbows utterly relaxed, like a pianist, sort of. Also, I bought a keyboard tray that supported a deep negative angle, which helped me keep a very anatomical (relaxed and natural) position. Also, figure out that mouse, somehow. Something like the above, plus switch sides frequently. I've no idea if that could help you, but after a few years, I'm largely in remission. I know this isn't really what you were asking, but I'm somewhat hopeful you can find relief. Good luck.