What spec was that - i’m looking at standard 4K tv’s here 
3840x2160 @ 60Hz
While a displayport to HDMI is not expensive - try to find ones that will offer 4k@60Hz is not easy and yes they do cost more it seems.
I am following a guy in YT that has just what i’m after and he’s running the main screen at 4K with the side screens at 2K, similar hardware to my setup too.