I got the same problem... Just use the alcohol to clean the USB C charging port on the phone then problem is fixed. Seems bad contact so that the initial handshaking to recognize the charger can't be achieved.
My Galaxy A71 5G will not fast charge after the Android update for December 2022 is installed. This is my main phone and I had a spare which was fast charging fine until I installed that last update. Now it starts to fast charge and reverts to regular charging. Obviously this makes the phone less than desirable because it takes too long to charge. I did all the terrible shooting. It's the Android December 2022 Update that prevents the phone from fast charging.
