Similar issue here with Aorus Master B550.
Seems to be a motherboard issue. I temporarily fixed mine by the following:
- shutdown the computer
- disconnect power (turn off, remove plug)
- press the power on button on your computer (to ensure the power is drained to on-board capacitors etc) - at least 10 seconds
- reconnect power
- startup
For me, this reliably restores the Bluetooth device and Windows can then turn Bluetooth on/off and the device appears in Device Manager.