iPad Pro 10.5 - what is "power supply" and is it really repaired?

iPad Pro 10.5. A few days ago text & images on the creen started to shudder on the screen and show an echo/shadow, and sometimes the screen wouldn't turn on at all. Didn't take long for the screen to completely stop working. If you are in a dark room you can see the backlight go on and off when you press the power button, but the screen doesn't show anything.

I guessed the problem might be a connector to the screen. I took it into Apple genius Bar and they ran tests by plugging it into a Macbook and the problem was the "power supply" (I'm sure that's what he told me). Problem is that I've searched for iPad power supply and can't find anything. Is it perhaps known by a different name?

Also, Given the "excessive damage" (their words) - a couple of chips on the metal on the corners, plus the device is a little warped which is only noticed when placing it face down on a flat surface (glass itself is fine, not even a scratch as I always use a case and a screen protector) - they won't fix it for free even though I'm well within the 2 year warranty period (Australian consumer law requires Apple warrantees to be 2 years instead of 1). They want A$715 (US$544) for an exchange. I could buy a newer model 2nd-hand or refurbished iPad for much less than that price. He said there is "probably other things wrong too", but given that it was working perfectly until a few days ago I don't think that is true.

My questions are:

1. ⁠what is the "power supply"

2. ⁠can it be easily replaced by a 3rd party repairer?

3. ⁠Any other options with Apple to fix a failed component where they claim the device has excessive damage?

4. ⁠Or is it not worth the inconvenience given it is a 4 year old device and should I purchase a 2nd-hand or refurbished iPad, or even a new current model??? (Time is money to me as I work a lot and I just want a working iPad for "home" use as well as self-education for potential career change).