The turning off existing colour management refers to THX, ISF, stuff, not basic settings capabilities as it does explain.
You must get the basics right using the minimum of controls, again as it explains in the user instructions.
I also doubt the colour temp is fixed at 6500K - no JVC I have ever looked at has ever been accurate.
But the results of a Quick Profile will tell you the underlying settings.
As it says on the user guide pages you need to get the basic right.
You should try setting to 'standard' if that is the only way to get access to the basic controls, and you should set everything as explained in the initial calibration page of the website.
You must get the underlying settings - all of them - as good as possible, including RGB Separation.
But, I would ideally send the projector back to who ever sold it to you as it really is not fit for purpose, and get a better one!
Mob Boss at Light Illusion