… there is no need to use “original” charger. Just use power enough charger, slightly “overpowered” charger is advantage as it is able to feed battery with “full” efficiency. I´m using 65W GAN charger for 2a with 45W max. charging power. When plugged, charger and phone battery “always communicate and negotiate” what power will be used.
Sometimes the problem could also be in “weak” cable, which is not able to transfer enough high ellectric current. But, original cable should be OK - but could be damaged/broken by simple using.
Anyway, always clean the USB-C port on the phone (always with non-conducting stick - wooden or plastic toothpick, thin sharpen piece of wood or plastic, etc.) at first, as this is No. 1 of slow charging reasons (pocket fibers and other impurities).
