Hold down gpio0, then press the reset button. This will put it into download mode.
Now you can flash or erase.

You cannot modify the bootloader in arduino-esp32- they are pre-compiled. Use esp-idf or lib-builder if you want more control.
The only interaction you can have with the bootloader is hardware level. That's why there is a strapping pin to disable the logging.

Arduino-esp32 is built as an extension to ESP-IDF. So, the arduino functions call down to ESP-IDF, which provides a lot of standard libraries. In this case, the relevant tools are LWIP, which provides an SNTP app, and stdlib time.h. The posix time functions will work, along with the handy C++ wrappe...

esptool != toolchain. It is a utility used to upload the data to the device.
It is using your default python, which is currently python2. Use update-alternatives to modify that. You can then test by running `python ~/.arduino15/packages/esp32/hardware/esp32/1.0.4/tools/esptool.py`

Your system is still running python2. I would suggest you move forward. Use update-alternatives to set your default to python3, and then use pip3 to install any missing dependencies.

https://github.com/adafruit/Adafruit_SSD1306 would be a good place to start.

Decode your backtrace with https://github.com/me-no-dev/EspExceptionDecoder
The esp32 uses 3V3, so your 5V input is being reduced by a power supply which may not provide enough power. If the backtrace indicates an issue in wifi or phy init, that does indicate a power problem.