I bought the BlitzWolf BW-FWC7 wireless charger for my Galaxy S9. Unfortunately, it charges just like my old wireless charger without fast charging.
Fast charging I have enabled, good quality cables (I tested with Ampere software: wired charging over 2000mA, wireless around 400-500mA), charger adapter Samsung 5V-2A 9V-1.67A. Maybe Samsung has a different standard for fast wireless charging? If I buy the S20 will it be the same problem and will I have to buy another wireless charger for fast charging?