There's quite a body of knowledge on body mechanics that doesn't seem to get much reflection in scientific publications. The only possible exception is the Alexander technique, and even this one is very much obscure. Not because it's secret or something like that, it's that these things don't seem to be searched for.
BTW, healthy writing (according to Palmer) is very similar: you rest your elbow and little finger on the desk and write by floating your whole hand above in a very relaxed way.
Practically all ergonomic studies start from the position of compromised wrist placement and measure what angle does least damage. That’s how you end up with split “ergonomic” keyboards.
This is the height you need for your monitor to not encourage slouching: https://www.youtube.com/watch?v=S467Ck8uIsc . You also need to touch type which not everyone can. As a result most office workers have terrible postures.
I bet you would run into trouble just trying to find enough people that can both touch type and have good enough posture to do such study. But I would start with piano players.
You can put everything in that list into 3 categories:
1. Fixing the problem: posture & monitor/keyboard height
2. Masking the problem: anything with the word ergonomic
3. Avoiding the problem: typing less/taking frequent (flow-interrupting) breaks
Of course most people with pain want quick solutions, so no. 2 is going to be over-represented. Fixing your posture actually takes work to stretch/compress different muscle groups over a period of time, otherwise you’re back to slouching after 10 minutes.
BTW, healthy writing (according to Palmer) is very similar: you rest your elbow and little finger on the desk and write by floating your whole hand above in a very relaxed way.