Hi,
[Note: I replaced my battery with a sketchy off-brand that constantly overheated before this]
I was replacing my iPhone XS back glass. While removing the pieces of glass from the back of the phone, I was using sharp metal tweezers, as something like a spudger wasn't very effective. Unfortunately, while I was removing a piece of glass that was on top of the wireless charging coil, I shorted (I think) my coil. There was smoke coming out of the phone, and I burned myself through the tweezers.
I tried turning on my phone, but it did not boot. I plugged it in, and it did boot. (It was at ~15% beforehand, and now it is at 1%.) I had the idea to let my phone die before I continued, although my phone was considerably hot (difficult to hold for more than 10 seconds). After it died I finished the repair.
I then tried to boot it after plugging my phone in. The apple logo pops up for a few seconds (around 3-5) before it disappears. It repeats over and over. I was able to get it to the restore screen, although after restoring the phone and the phone restarting, it just goes back to the boot loop. While any one of the screens is on, if I unplug the phone it dies immediately.
Here's what I think is happening (with my limited experience):
My phone's battery is dead, to the point of 0%. The capacitors are able to hold a charge enough for it to go to the restore screen or the first few seconds of boot, but otherwise, there is no charge. I have experienced a 0% battery before on another phone, and it would go into the same "boot loop". The reason it can go into the restore screen is that it is a very low-power screen.
Currently, I am thinking of taking it to the Genius Bar and getting advice on this or the battery replaced. If any of you can provide me with your thoughts, that would be amazing.