I actually tried some 2d to 3d conversions myself a couple of years ago with reasonable (but incredibly slow) results (that was using a google colab that built a depth map for each frame and then created an image for each eye, similar to this ).
I tried wondershare 2d to 3d after seeing this post as I was curious. I'm not sure, but I think it might just be delaying one frame (similar to this). It seems that it could work ok, with some lateral movement in the scene, but I didn't get any good results with what I tried.
Some parts of extending this to VR might be possible, but I don't know of any research that's been done. In theory, it should be possible to stitch a load of frames together and build up a 3d environment in which the scene takes place. That should be the 'easy' part. The major issue I see with that is that you don't know if anything outside of the current 2d frame is moving. As the camera pans down to the girl's pussy, her upper body would freeze in place without some way of predicting how it's moving.
TLDR: I think 2d to 3d is the realistic limit atm, but even those can work well in VR with a well selected scene. I might try looking at this again in case there's anything faster out there now...