iPad charges up to 1% but then dies again

For a few days now I’ve been having issues with the battery on my iPad since it wouldn’t show that it was charging until I restarted it. But yesterday it wouldn’t charge no matter how much I restarted it.

I tried plugging it in to every charger that I have but none of them would work. The battery drained fast and it drained even when it was turned off. I brought it to the Apple Store and they said they didn’t know what the problem was and I should just get a new iPad. They also looked into the charging port and there was no damage and all of the pins were intact.

This morning I tried to plug it in again and it started charging! I waited for a little bit and it turned on with the battery at 1%. It stayed on a few minutes before it died again (The iPad was still plugged in and even showed that it was charging). Then it charged to 1% again and then died and the process repeated.

Just now I watched the iPad turn on. I thought like the other times it would be at 1% but it was actually at 4%!!! But then immediately went back down to 1% so I shut it completely off to see if it would lose battery. I just turned it back on again and it was actually at 5% this time??? But then immediately went down to 2%??? I am very confused. The battery is still draining even though it’s plugged in.

What I tried:

• hard reset multiple times
• Cleaning the charging port with a toothpick and toothbrush (when I tried cleaning it with a toothpick, black stuff came off onto the tip and I don’t know if that’s dust or grime or if I missed something???)
• Updating the iPad to the most recent version

Extra info

• a few months ago I dropped the iPad when the charger was still in it. The iPad was fine but the little metal part on the charger that goes inside the charging port was snapped off and got stuck inside. I was able to remove it but maybe it caused some lasting damage??
• Ever since then I had to use an old charger that I had and the iPad has been charging, but a lot slower. I don’t know if that’s caused by the accident or because the charger is old.
• I heard that iPhone chargers are weaker iPad ones, and the other chargers I tried to use were all iPhone ones. I don’t know if that’s a factor in this. However when I went to the Apple Store they tried to charge the iPad with one of their chargers and it still wouldn’t charge. I don’t know if they used an iPhone charger or if my iPad just really wouldn’t charge.
• I’m traveling right now so maybe the voltage in the place I’m staying is also weak?? But I've stayed in this place before and it’s never been a problem before and my iPhone is still charging fine. But I don’t know the voltage for the outlets here or for the chargers that I have.
• I don’t have warranty on the iPad and I don’t have the original iPad charger with me.

Please help!!!! I really love this iPad and I just want it to charge normally!!