The 120w charge is slower because:
The phone is a 120w fast charge, which is mainly charged by the high-voltage input battery. After a long time, the power of the battery decreases, and the input power will weaken, so it is not as fast as before, unless the battery is changed.
To achieve fast charging, the mobile phone needs to match the charging protocol, and then at the same time require each interface to be in good contact, if there is bad contact, it will lead to a significant reduction in the charging current, and the charging speed will also decrease significantly.