I've noticed there's quite a few settings on my TV that are greyed out and I know this can be dependant on the source but it seems to be the case on all imputs, in particular under display the PIP and advanced settings are greyed out, feels like it's in demo or shop mode but it isn't
Also got issues where the TV just restarts randomly, I've also ran the anytime+ scan several times but it never changes the source when I switch between imputs, like changing from my STB to my samsung blu ray player or my xbox one, always have to do it manually
Only had it around 6 months and don't wanna really have to get it exchanged
I have found several issues suddenly arise from time to time with my Samsung QLED. Greyed out setting features, remote not paired, etc... I turn off the tv, unplug it from the outlet, then plug it back it. This works as a fix for many issues. It worked to reset the setting options so that all are available.
Some other settings were greyed out one our Samsung smart Tv. How i fixed it was that i put the tv in demo mode, and switched it back to personal mode. Then all the settings were selectable.