Hi Mousab,
The USB-C connector used on your phone has a lot more pins to it than the original USB-A connector had; it's up to 24 pins vs. the 4 or 5 used with previous USB revisions like USB mini or USB micro. From the website [link|https://pinoutguide.com/Slots/usb-type-c_pinout.shtml|USB-C (Type-C) pinout diagram @ pinoutguide.com|new_window=true]:
[image|2756145]
Many of the new pins have to do with the fast charge capability and allow the phone to communicate with the charger to tell it to put out a higher voltage so it can charge quicker. It sounds as though one or more of those extra pins has been damaged or blocked, leaving only the basic original USB charging function working.
I'd suggest examining the pins on the phone's USB connector carefully with a magnifying glass and a bright light. You might also try cleaning the port with high alcohol content (90% or above, not the 70% stuff we all normally have around the house) and something thin and non-metallic like maybe a toothpick.
Let us know what you find. In the worst case you could end up having to replace the charging port, which is very doable and not prohibitively expensive.