Overtime in mainland China is hard-ceilinged at 36 hours per month (1.5 hours per day...). Beyond that is illegal, which is likely in large part why 996 companies don't like the spotlight in the current 'who knows' game of who Beijing/Xi will selectively select to be made an example of.

Triple hourly pro-rata pay is only for working over official statutory holidays, otherwise overtime pay is 1.5 pro-rata hourly rate for working days and double hourly rate for 'rest days' (this would include Saturday or Sunday for a Monday-Friday employment contract).