Thank you all for your suggestions. After a month or so on a normal keyboard, my hands are feeling much better, so I’m going to try my Keyboardio again.
I’m going to start really simple. I’ve constructed a cardboard stand for my laptop, so that I can place my Keyboardio halves closer together.
It will also let me push my Keyboardio further back, which I think was the big problem with my last setup.