Everything says it’s over 4K per eye and that you can have a 4K virtual monitor. Where are you getting your numbers? I can’t find anyone saying 3.3K per eye and 1080p screen.
https://www.reddit.com/r/virtualreality/comments/142kz7x/app...
So 3660 pixels horizontal (already smaller than 3840 pixels for 4k), and that's for full field of view.