Power-cycling the board might have an effect. I believe the bootloader will default to the OTA upgrade if the firmware upload failed, but if it succeeded and put bricked code into the unit then I have no idea
This doesn't help. The BLE module appears dead - it doesn't send a boot event on its serial port, and it doesn't start advertising on the air.
If you have an external programmer and access to the JTAG/SWD pins, then you can reprogram the chip if the firmware on it is bricked.
The minimum is a 5-pin connection to the chip to reprogram it.