do you remember the illustration used for this post? it was showing a flip-folded phone with no external display.
I measured my pro with an apple case, it was 11mm thick, that's about 0.43.
so it is indeed thicker than the pixel 9 fold - according to the specs is 0.4" which is 10.16mm - by less than a mm.
the iPhone w/o the case is 0.31", so 7.8mm - so 2mm thinner than the pixel.
I'm not a fan of overly thin personal devices as they need some level of rigidity, and I believe that the pixel 9 fold is not too bulky either. but it is a brick if you consider it's weight: 257g which is more than half a pound.
there's no free lunch. and people put cases on their phones for a reason, or at least I do it for a reason. you don't put any case on the fold 9, because it is not possible. whether you think it is a limitation, I don't know, but I sort of believe this makes the device more vulnerable. same goes for debris getting between the folding screens - I would say this is not ideal, but that's just my personal opinion. maybe it will never happen to many.
still, the fold 9 has at least some practical use with the 3rd screen, it can be used as a normal smartphone without being forced to open it every single time. but please remember: my rant was primarily targeting the flip-style foldable devices, which is just a dumb idea capitalising the novelty factor without truly considering actual impacts on user experience.
and I have my own concerns about the screen aspect ratio of the horizontally folding devices too, but that's more like a matter of tastes: you seem to like it, while I don't - and I won't start no war about it