China's 996 or 007 work schedule is created by desperation. The root problem here is that almost all good industries in China are already cake-spliced by the powerful and privileged, leaving very little for the private sector to compete. As result, every tested and true way to reach profitability is a combat in the bloody sea, which in turn caused the hellish schedule.
So, if you see a SF start up founders started praising 996 schedule, keep a watchful eye, make sure those founders are not in similar desperation.
Also, Elon Musk loved China schedule, I don't really see Twitter improved much since.