Thanks for trying to help me! Seems like you don't have the latest Windows version. My version is 1909, 1836.628. But I have tried with the July 2019 (I believe) 1809 version, and that has the same problem. And my OS has no problem controlling 3D settings when I use PowerDVD and fire up a 3D Blu-ray, it goes to 3D.
I may be wrong, but I thought that leaving 3D on in the NVIDIA control panel shouldn't do anything as long as the OS or a program isn't switching to a 3D desktop resolution. If that actually does something, it only affects madVR HQ, nothing else.
My 3D setting really doesn't need to be like the ones you show, because I won't be using MC to play back any 3D. I hav to use PowerDVD for that, as I said above, even if I hoped that I could avoid it. But MC can't (as far as I know) do menu based navigation of Blu-rays and ISO's, so that's really a no go.
I did the back and forth with Windows Display settings and NVIDIA control panel, and Windows is able to change the settings in the NVIDIA control panel. But that's counter productive when using something like PowerDVD, because PowerDVD automatically makes the change from 4K to 1080p 3D when you open a 3D movie and then back again when the movie stops. But if stereoscopic 3D is off in the NVIDIA control panel it can't do that. So the best way to do it is to leave that on and don't mess with the Windows display settings at all. If I do, I'll have to manually change that in display settings every time. Alt least for me to activate stereoscopic 3D in NVIDIA control panel that doesn't change to a 3D resolution, it only makes it possible for PowerDVD to do it when necessary.
As for HDR I have no equipment that supports it, so I have never touched that setting.
My projector is a JVC DLA-X500R-ILA, so it's a model or two before HDR came in to play.