No one setup helped me either. What did help me was recognizing that I had a problem and actively changing things - like varying small setup changes like angle to the table. That was mostly enough to stop stressing always the same parts.

The Kinesis (and now the Moonlander) has really helped with the pain in my hands from severe nerve damage (from a coma) though. I understand it's not exactly RSI, so the mechanism is different. I agree with you about exercise. At this point, I'm nervous to rely on just one single change, so a multi-frontal attack is needed. A consistent stretching routine is probably what helped me deal with pain the most...

Just to counteract your latter point, switching to a split key well keyboard with good palm rests did largely solve my wrist issues.

Of course, every person and diagnosis is different.