FWIW; my phone (FP3) had experienced sudden death overnight (annoyingly causing me to oversleep as the alarm didn’t go off). After reading this thread and watching the Youtube video @Paule posted above, I decided to try to reflow the chip.
I didn’t have a spare oven, but I have a heat gun and one of those laser thermometers. I slather the chip in soldering flux and then used the heatgun to heat it up, using the themometer to make sure it went over 200°C and the flux was boiling.
Reassembled and I felt a vibration when I plugged in the usb-c cable (hurrah!), but it died again about ten seconds into booting up. Tried reflowing again, but to no avail. Clearly the issue was indeed that chip as identified in the video, but I suspect I overheated it and damaged some other chips.
Shame, but glad I gave it a shot.