With respect, that’s just one opinion. To my eyes, there is a huge difference between the Universal Blu-ray and the Arrow Blu-ray, as we discussed when the release first came out. I haven’t seen the UHD.
Indeed, we did previously discuss this, with screenshots. I'm still not seeing the huge difference you do, but this isn't a thread about that movie so I'll let it go.
As for Rules of the Game, I have a hard time understanding the point of a UHD release given the condition of the surviving elements.