The best panels for color rendering are IPS. They aren't all created equal either, some IPS provide better color than others. I'm sure there are lots of comparisons out there for budget, mid & high end IPS monitors for photo editing.
IMO if you are going to edit 4K video, you would probably want to do that on a 4K monitor.
You don't need more than 60 Hz refresh rate or the premium you will pay for G-Sync variable refresh rate. Having 144 Hz refresh rate & G-Sync are more useful options in gaming monitors.
Hope a few of those points help out.