I resent the idea of an absolute standard of ergonomics or typing technique. I often use my left thumb to key z/x/c/v/b. I often reach with my left index finger to key y/h/b. During certain chords, my hands often cross over the split. I tried multiple split keyboards over the period of 2 years and never grew out of these habits. I always wished, at the least, that some of the middle keys were duplicated between the t…
The elephant in the room with the 'ergonomics' argument for split keyboards is that you get a marginal improvement using the keyboard this way and ten times the effect by just getting up and going for a five minute walk every hour or so.
The same goes for mousephobia, which overlaps with split layout users. I still use neovim every day, but the quickest cure for the CTS symptoms that 'ergonomic' keyboard purist vim users seem to get much more than their IDE coworkers is just moving your hand to do something other than type in the exact same position for hours on end - something like grabbing a mouse. I strongly suspect that CTS in software engineers will go down in the next coming years as coding agents become more common and SWEs pick their hands up more (or just physically type less).
The same goes for back pain, if you're otherwise ablebodied enough to start resistance training it's infinitely more beneficial than whatever chair you're looking at.