This doesn’t really answer your question but I was on Jury Duty recently and was disappointed to learn that the stenographer was using a normal QWERTY keyboard and boring Dell computer. It seems that they used special software however that was connected to an audio feed with some recall ability.
That being said there is some [support for stenography in the QMK programmable keyboard firmware](https://docs.qmk.fm/features/stenography). I’m not sure how widespread its use is.