When we moved to WFH during the pandemic, the company subsidized some equipment and I ended up getting a different type of kneeling chair from the same brand: this one rocks back and forth and is also great for fidgeting. I now have both chairs in my house and use them interchangeably (with a small preference to the rocking chair these days). It does not magically fix my posture, but I've had no back pain at all since switching.
Both chairs are from Varier (Wing Balans and Variable Balans)
Work wise, I've tried many chairs, which evidently were not all the most ergonomic, but what I noticed was that it's mainly caused by weak core/back muscles.
So I just want to mention that an ergonomic chair wouldn't be a solution by itself if you're in the same situation as me, strengthening your core should be a very important thing to take into account as well.
I started to cycle between standing, sitting and laying on a couch with a laptop. works well for me. WFH.
Tried Diablo V-Basic from Poland. Altough the back support was nice, my ass hurt. And a pillow simply didn't work on it, so I sold it.