I have no idea. With GPU similar to what Quest has at the moment, with breaking rendering into such big tiles, it might be unusable but then - if the area is big enough, you may not be able to notice, as peripheral vision is quite blurry and wherever you look, you should get only the sharpest image.
There were some companies that did eye-tracking stuff for Quest. It should be fairly easy to test foveated rendering if one has access to this hardware.