Great topic and an interesting link Maru!
Honestly, I am always confused about the direction I should go in. I like the slim, super back supporting chairs but honestly, since I work from my home office, I sometimes like to get in a position that can only be described as "half laying" in my chair. Helps me rest my back muscles and get in a different position than the typically "straight up" one. So that said, the Ikea Markus doesn't look too comfortable to do that as its just not big nor puffy enough. Then again, those bigger "puffier" chairs typically do not offer as much back support as you'd expect.
So maybe I'm just weird and I should stick to just always sitting up straight but either way I echo the OPs message - Any help is greatly appreciated :))