Phone charging very slowly

• Try a different cable. Cables wear out faster than phones.
• Use an adapter that matches your phone's fast-charging watt rating.
• Check the port for lint and clean it gently with a wooden toothpick.
• Plug straight into a wall socket instead of a laptop USB port.
• Turn the phone off while charging to compare the speed.

A loose connection that needs wiggling to charge means the port needs repair.