I have a standing desk, but I often find it hard to concentrate while standing for very long periods. It has made stuff slightly better. Also setting up everything to avoid mouse has made my problem less acute.

Could you share your experiences with ergonomic chairs and desks that have worked for you?

From my rather lengthy research, I have found that the optimal setup could be a low 135 degree reclined chair (e.g. Herman Miller Embody, which unfortunately lacks a headrest), a slightly inclined curved desk and a low declined keyboard (e.g. Microsoft Sculpt, Keyboard.io).