just got my M5Stack Fire delivered this week as well (from a store in Switzerland) and facing similar problems:
When switching on, the screen stays black most of the time. (Now it already seems to stay black all the time)
When switching off, strange noise when the power button is pressed.
When booting, I see normal boot messages on UART over USB.
Charging the device also works.
I have erased/updated the firmware with M5Burner several times, but does not help.
I can even program it with UIFlow, e.g. RGB bar or speaker work nicely, but the display stays off.
Unmounting the M5Go Base (bottom with the battery) and powering the device over USB alone does not help!
Shorting the battery does not help neither.
The battery power is 4V, what is fine for a LiPo, so the battery seems OK.
When powered over USB only, there is no more noise during power button presses, but I cannot switch off, only restart the device then (may-be intended?).
It is really a pity, M5Stack builds such nice devices, environment, with lots of documentation (although still not perfect) and community. And then quality issues make it unusable!