I don't believe anybody's going to be able to diagnose anything for you without being able to inspect the tablet. My suggestion is to find the nearest UbreakIfix repair shop and take it there for evaluation.
we are so sorry to hear about the charging concern you're experiencing with the tablet and would like to ask additional questions to assist. Have you tried testing your current wired charger with a different device to ensure appropriate power is being provided to the tablet? Can you test the charging port of the tablet with a different wired charger? Finally, have you tried charging the tablet with a PC?
