I'm using a linear columnar split keyboard now (moonlander from zsa, redox from falbatech before that). That has done much more to reduce strain than anything else I tried.

I would also highly recommend getting a trackball, personally I'm a programmer and have to rely on my hands despite having RSI and CTS.

I was getting RSI constantly no matter what ergonomic keyboard I had (MS sculp or whatsitsname was the only one bearable), eventually I got a programmable split keyboard, ZSA Moonlander - RSI immediately gone. But apparently that was even an overkill, I loved the programmable part so much that I decided to buy Planck for my gaming pc because it's tiny and can fit on my couch-mouse-pad setup... No RSI either! I use it for programming too now. I have a theory that what was hurting me was the need to move fingers to backspace, ctrl, etc. And maybe the staggering as you need to twist your wrists a little all the time. Ortholinear feels just... more sensible, for muscle memory... From now on I buy only ortholinear programmable keyboards, they are fun, make more sense, and don't get me RSI!