I will throw in my 5 cents anecdata (I have a history of trauma/back injuries and pain).

I spent about 100 euros on a kneeling chair, that had enough adjustment settings for my liking. I have been increasing my time on it steadily for the past few months, to the point that I now confortably work the whole day from it.

It is a complete mind shift, I actively have to sustain my posture (and actively shift it), I don't slouch and I don't snooze off. It propels you into 'active mode'.

Whenever I am eventually physically tired it prompts me to take a break by taking a walk or eating a snack. I have been absolutely back pain free for the last 8 months and overall I feel that my posture is improved.