I think Unity already does what it can in this respect (all VR supporting engines do AFAIK). Is this your actual issue?
I just want to provide explicit control over it to my players. While the performance impact of disabling it can be quite big, there is always at least some reduction in input lag, which I know some people prefer. This is especially noticeable when paired with a framerate capped far below what the system is capable of, e.g. when using vertical sync on a display with a low refresh rate.