Based on the cost of a high performance single 4K HDMI output video card, I can't imagine the cost for what is likely a rather rare 4Kx4 card would cost nor the real need, nor the power it would consume, while stressing the computer PS.
No worries, I can afford it. Had my vision deteriorated like this earlier, I might have gone with a large television as a monitor. C'est la vie.
