Hello,
Playing on immersive mode has made me use rations, however, at least one of them seems to need a rework if they are to be useful in any way with immersive mode, which I think they should be. I haven't tried all of them, but want to make a suggestion on the one that I found the most apparent.
The health regen speed should either start health regen when health regen is disabled or it should be reworked for some other purpose.