You wont be able to drive 1 4k TV much less 3 with just 1 card no matter which one you get. So unless you are prepared to spend in the neighborhood of $3-5k on vid cards to drive those TVs, unless you arent gaming. But what other purpose would 3 4k TVs serve? Commercial application?
The Sony receiver has 3 hdmi outs and is HDMI 2.0. I realize there isn't a HDMI 2.0 card right now. My idea is for the receiver to do the work.