Many years ago I too had pain in my wrists while doing lots of programming work. For me the game changer was using Vim and mapping ESC to jj in both the editor and the shell (via .inputrc). In fact I mostly use Vim because of the provided ergonomics, the fast editing capabilities are just the cherry on the cake.

In my opinion the main culprit are modifier keys (e.g. by default the shell uses emacs bindings and you do a lot of ^A, ^E, ^R, etc.), but using jj mostly solves the issue as you just have to reach for Ctrl when you require SIGINT or copy/pasting in different environments that do not support vi keys. There are also people that remap it to Caps-Lock, but I just don't like to use my pinky that often.

Of course, everybody is different, but it makes sense to think about a setup that suits you and your health.