An adjustable office/shop stool might work but I generally need to stand to work a knife well because sitting at a table brings the cutting board up too high, where my elbow is at the wrong angle for it. Also for an office chair, the arm rests might be in the way.
Depending on how much room you have, you could build a small rolling island/butchers block that is as tall as you want it to be. You could easily justify the costs (probably) if you are already getting hit with back surgery and neck issues. Something like this, but taller and wider might be feasible to build yourself (edit: more at the bottom):
View attachment 528757
Otherwise get a commercial dish rack and set it upside down to work on. You could even epoxy some rubber strips to it, to keep it from sliding around, if that becomes an issue:
View attachment 528758
Edit: Found a nice enough looking DYI. Looks like it's using
Kee Klamps and aluminum railing, but you could use cheaper
black iron pipe and coat it with
Flood to prevent rusting (there are also proper ways to paint the pipes).
View attachment 528763
