The Euro version of the Qn90a has IPS panel so i m guessing you saw the VA version of the QN90a which is for the US market?thanks for this explanation as I had observed this myself and did not know the reason why.
I compared playing 4K HDR Top Gun on the QN900A (8K) vs the QN90A (4K).
I observed the QN90A first. Then on then viewing the 8K TV , I was immediately struck by the letterbox black bars not being as black and as good as they are on QN90A, almost like it was a IPS panel.
it was for this reason that I ruled out the QN900A , even though I much preferred the design and virtual zero bezel of this flagship TV.