I think you're best giving up
on the format then.
4K's 3D's replacement.
But 4K and 3D are really Apples and Oranges. One is just an improvement in clarity and resolution and the latter is more emmersive with its illusion of depth perception
I must tell you though, there is no substitute for watching a well made 3D film on a flat HD screen at home. Of course it puts low lit badly 3D converted theaters to shame, but it even bests IMAX Theaters. The crisp 3D adds so much, I don't believe I could watch "Avatar" or "Guardians of the Galaxy" the 2D way again. The wonder is real.
I own precisely one 3D blu-ray, and that's only because the unrated cut of The Wolverine was only available in that set. And it's not even on the 3D disc.
Yep, the 3D version is a separate disc.