If the charging cable won’t properly seat or easily fit into the charging port of the iPad, this might indicate that either dirt or lint is obstructing the plug, or the plug or charging socket have been damaged. A damaged charging cable must be replaced - whereas a damaged charging port must be repaired.
If the problem is due to a visible obstruction, you may be able to remove it yourself*. With good light, using a sharpened wooden matchstick or plastic toothpick, very gently try to dislodge a visible the obstruction from the socket. Be careful to avoid damaging the delicate electrical contacts within the socket. Note that a USB-C socket has an obvious "tongue" within the socket.
You might be best advised to visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad. If repair is required, you'll be in the best possible place to explore your available options:
Genius Bar Reservation and Apple Support Options - Apple