Is there any sound at all coming from the bank or is it completely silent when you press the button?

I don’t have my box in front of me, but it sounds like the tray isn’t returning to the rest position fully. When you disassemble it, is there anything preventing the tray (where you put the quarter) from smoothly returning to rest position?

It seems like a lot of steps have gone missing from this guide. The related guide (5SE) has much more explicit instructions for the same activity and should be used instead of this one. iPhone SE Front Facing Camera and Sensor Cable Replacement

There is a nub on the inside of the case which is attached to the battery. When you try to pull it open, it appears to be attached to the plastic casing of the battery, which sometimes splits. I gently unhooked the nub from the battery before removing the case fully. This seems to happen if the battery has suffered some drop damage (plastic parts broken around screws and parts of plastic frame split). Just an FYI in case your lower case doesn't pull away easily.

When I started the phone again, there was a grid pattern and touch was not working consistently. It turns out there were two separate problems. (1) We had over-handled the cables and a quick swab of alcohol helped remove the oil from the connections. (2) The first connection is really tricky to get right and comes undone easily during the final reassembly.

Confirming the fix of switching to the proper charger. I had a 2011 MBP that died (no click, no whir, nothing). Swapped the 60W charger out for the recommended MagSafe 85W charger, started up no problem.

It's an easy first test for the solution before delving into the other possible issues.