Tesla is so far from buying shares back. They could invest in targeted grid scale energy projects that could have a five year payback. Not as fast as the payback on a gigafactory, but far better then most stock repurchases.Just keep the cash, or pay down debt IMO.....
Reducing debt, or investing the cash in expanded capacity, creates value for shareholders...
When debt is zero and they have no plans for significant Capex, that may be the time to buy back shares.