I have correctly got a microbit working with serial communication via COM port USB.
My aim is to use COM over bluetooth to do the same.
Steps I have taken:

(on windows 10) bluetooth settings -> more bluetooth settings -> COM ports -> add -> incoming
in device manager changed the baud rate to match that of the microbit (115,200)
paired and connected to the microbit
tried to write to both the serial and uart bluetooth connection from the microbit to the PC (using a flashed python script)
using Tera Term, setup -> serial port... -> COM(number - in my case 4), with all necessary values (including 115,200 baud rate)

After doing all of these, I see no incoming message on Tera Term. Have I missed anything?
This is not directly possible via BLE UART communication because it uses different protocols (as mentioned above by ukBaz).
You are able to, however, communicate via custom BLE libraries such as bleak.
Bleak has some good examples on its github repo of how to scan GATT characteristics and services to find the TX and RX characteristics of your BLE device.
From there you're able to connect to the microbit directly over bluetooth and read and write to it's GATT table and not using the proprietary BLE protocols etc.
I'll make a tutorial at some point and link it back here when it's done.
Using serial ports over bluetooth with micro bit