ime, my rsi wasnt helped by stretching my hands/wrists at all. I tried many different mice, seating positions, chairs, grip styles... a whole body approach worked best. my shoulders, neck, back, and chest being locked up was the actual problem. as well as unfreezing my hips/psoas so I could sit more comfortably for longer
anything that causes systemic inflammation like alcohol, excessive sugar - avoid if experiencing any pain. there are a multitude of tiny things that can cause nerve and muscle pain related to diet; lack of magnesium being a huge one, lack of glycine (collagen-producing) being another one.
I play jazz guitar, play slippi almost daily as a spacie main, and spend a lot of time on the pc, and my pain has been reduced to an almost non existent level. also, listen to your body, it knows when to stop