@rune No experience with this myself, but I do vaguely recall seeing some designs at some point that opted for making things controllable with elbow movements rather than wrist movements (mainly by being big enough that one can push down on it with their arm if they so chose). No idea if that even approximates an ideal solution, though.
@joepie91 I think using elbow movements is probably too big/crude a design in this case as she does have some mobility, it's just the rotating your arm 180 degrees part that's rough.
Some of the designs I've looked at seem to just focus on giving more leverage by either attaching the key to a handle or by making an attachment to the key that gives it a more elongated shape. I might just have to print it and check if it makes it possible to do more of the movement with finger movement instead of wrist rotation