Switching to a planck keyboard would let you customize all the positions of buttons for less strain.
Ergodox, Diverge, Keyboard.io, really any split key keyboard does worlds for keeping hands straight and are fully programmable to very high degrees.
The best way to describe it is that the home keys aren't ASDF, but more like WEFV with my forearm angled so it's straight from elbow to fingertip. This exaggerates the effect but demonstrates it clearly; the real home positions are more like intermediate points between keys.
I've actually had a Planck EZ for a few weeks now and I agree it's probably not very ergonomic for the classic qwerty touch typist, or at least not much better than a normal keyboard barring the programmability.
But since I don't do that anyway I find the keyboard to be pretty nice in terms of customisability and avoiding stretching.
In general I feel my hands are used most naturally in close proximity to each other (at roughly abdomen height) so I'm drawn to small keyboards with lots of modifier keys. A spherical keyboard would be pretty interesting to try out.
If I outstretch my arms, straight, my index fingers are pretty much in line with my shoulders.
So no, when I use my regular unsplit keyboard my hands/wrists are not straight, because my shoulders are not 60mm apart..? Am I missing something?
It does sound interesting. I did type this comment trying it, and it was pretty comfortable, with the exception of my right wrist. That being said, I've got kind of weird seating set up.
If I stick my elbow way out I can make 'wefv' as natural to me as 'asdf'. So I suppose either my elbows are more tucked in, or my keyboard's wider ('dfgh' for example contorts the other way, and analgously to 'wefv', 'rthn', or better but less analogously 'erth', is more comfortable there).
The Planck keyboard is cramped. It's worse than a cheap Microsoft ergonomic keyboard.