Need Help With 43 inch 4k Vizio Problem Please

Hi all:

Well, my 1080p Vizio TV monitor died and I had to replace it. So I went with a 43 inch Vizio "4K" 43D 2018 TV to replace. Hooked it up and mostly everything is well except for a couple of questions. These things don't come with much documentation and I've researched this on the web, but 3 questions still stand:

1. With my earlier Vizio when you launch the nVidia Display Manager, or whatever it is called, and open the page "Change Resolution", there is a choice box at the bottom for the "Full Dynamic Range" on colors. On the other Vizio you could check "Full" and it made a huge difference in the picture quality. With this Vizio, that box is grayed out and stuck on "Limited". Any ideas on why that is so?

2. The 43D has three HDMI ports. Can I assume they are all the same as far as picture quality goes? Thoughts?

3.I am having a difficult time choosing the "Picture" selections on the 43D set up box. As you are aware if you have one of these TV displays, there is a list of picture quality choices such as "Computer", "Game", "Television", "Calibrated", "Dark Calibrated", and maybe more. The choices are noticeably different. Is this a matter of personal preference or is there a particular choice that is known in the community as best for FSX looks or performance?

I'd appreciate any thoughts you can share on these issues.

Thanks

Rick