The solutions can be as follows: If the phone is charging slowly, plug and remove the charger several times, check whether the connector and jack are clean, if you find dust, it is recommended to wipe with alcohol or clean it with a brush.
The ambient temperature is too high or too low, there will be slow charging, if this is the case, you can take the phone to the normal temperature place, and then charge it after the temperature is normal.
The situation that Apple's mobile phone is also very slow to charge with 20w fast charging is generally due to the problem of serious aging or damage to the battery during charging, which leads to the problem of slowing down the charging speed