Force bluetooth usb adapter Mac Catalina I'm having trouble forcing my mac to stay connected to my external USB Bluetooth adapter on reboot/restart.

I've read quite a few posts and have found this command

sudo nvram bluetoothHostControllerSwitchBehavior=always


I was able to use Bluetooth Explorer and I switched it to the new bluetooth USB dongle but it will still not remain connected after reboot. Instead it remains disconnected and I have to reconnect it every time I restart my computer.

Machine:
2018 Mac Mini

Current OSx: Catalina 10.15.5

External Bluetooth Adapter:
Asus BT400

https://www.amazon.com/Bluetooth-Receiver-Keyboards-Controllers-USB-BT400/dp/B00DJ83070

Their are windows drivers but not for mac since it uses the same Broadcom chipset.

Is there another command that I can use that will keep it connected after reboot?
I think that the macOS system integrity protection is stopping your external Bluetooth adapter from getting reconnected after a restart.

You could disable the system integrity protection (https://www.imore.com/how-turn-system-integrity-protection-macos) and try again, but this is not a permanent solution since you shouldn't disable the system integrity protection.