4:4:4 and full RGB are essentially the same thing. As long as you are running HDMI 2.0, you should set full RGB or 4:4:4, as it should have no issue all the way up to 4K 60p. Do not use 4:2:0, this should only be used if you are trying to squeeze 4K 60p through HDMI 1.4
Concern yourself more with the RGB range, your TV has a "PC" mode (don't confuse it with Game mode, which is still a video mode), if you use that then you can output 0-255 for computer use only. You should not be using this configuration for watching movies. If you don't want to flip back and forth between configurations, then leave it in Game mode and feed it 16-235 for everything. The TV expects that signal and will expand the dynamic range back to full (and it may actually even look better because the TV's processor does other clever things in video mode that it doesn't do in PC mode). But do not send 0-255 in video modes, you'll be crushing whites and blacks.
Read more about your TV here
http://www.rtings.com/tv/reviews/samsung/ju7500