Of course, but the 4680 Y in Austin is being manufactured this year, possibly even right now. The cells aren't provided by this plant in Japan, they are currently being provided by Tesla's own equipment in CA.

I'm just guessing as to how they might use these cells that won't be produced in volume for at least two years. To me, new vehicles that haven't yet been announced are the most likely candidates. That could easily turn out to be wrong, of course.