Configure SSH, overclocking, firmware, WiFi, Bluetooth, VNC, and two-factor auth for a headless Rasperry Pi 4B with Raspberry Pi OS

This stoy will be very similar to my last two about the Raspberry Pi, but in this case, we are going to use the new Raspberry Pi OS (previously Raspian) which is based on Debian Stretch (10) and a Raspberry Pi 4B with 4GB of RAM which I recently obtained.