You can use 33w
The Mi 18w and 33w chargers are universal. However, if the 18w charging protocol mobile phone uses a 33w charger, then the charging time will not be reduced, because the mobile phone only supports 18w charging, so the chip in the mobile phone will limit the charging power to 18w, so as not to damage the mobile phone battery.
If it is a 33w charging protocol mobile phone, with 18w charger, the charging speed will be slow, because the charging power of the charger is only 18w, so you can only charge the mobile phone with 18w power
Absolutely, because the current smart phone charging is backward compatible, through the online data we can know that millet 12x, as the flagship mobile phone of millet, has a 4,500mah battery and a charger of up to 67w charging power, so it can be completely charged with 33w charger, which can be said to be a basic common sense. Most phones will do.