Diagnose a faulty charging port

Hi,

I have an Ipad air 2 that doesn’t charge now.

A couple of month ago, I dropped it with the cable in, and unfortunately it damaged something inside.

But for some weeks, it charged anyway when i pushed the cable down so I thought it’s the port that had been damaged.

After some days, suddenly it lost it’s audio and a week later it stoped charging.

It recognized the charger when it’s plugged in (turns on the screen. but it isn’t recognized by pc or itunes) And it’s fully drained now.

So I took it to a repair shop to change the lightning port and unexpectedly, they told me it’s mainboard that is damaged not the charging port. They said also they tried to changed it and didn’t work.

And the battery is swollen also.

I took it back without repair because they asked me quite much money as a used one.

I still have doubt if it’s the logic board problem really.

Is there any way to diagnose the charge port and the logic board by myself if they are working properly?

Because it charged anyway for a while and it lost the audio, too. I read it could be a problem of charging flex.

Or it can be just a battery problem that the system prevents it from exploding?

Thanks for reading