Hi,
As the title says, My phone was working fine, then died due to low battery. nothing abnormal there.
Once I connected it to the charger (normally at this point it would start-up, it didnt) I left it for about 10-15 mins before attempting to start.
I couldn't start it by holding the power button normally, i appear to only be able to get it to power on by loading into fastboot mode, then starting the device.
As soon as it loads up to the OS (pin code unlock screen) it turns off after a few seconds. If I leave it in fastboot mode, or even pause it before it loads GrapheneOS, it will happily sit there for a decent length of time.
In that short length of time, I'm able to unlock the screen very very briefly before it seems to power off.
Edit: The device does the same if booted into safemode. It displays it has approx 50% battery now too.