Getting Bluetooth on Windows 10 Virtual Machine (Guest) - VirtualBox / Disabling Bluetooth Daemon
The problem with this, is that the host (your Mac) needs to completely release the Bluetooth adapter so that VBox can take “ownership” of it.

To see what’s loaded issue the command.

kextstatus | grep -i bluet


All of those kexts need to be unloaded.  The problem is, macOS will respawn the processes automatically.

There’s a couple options you can try:


use a seperate USB Bluetooth adapter
Use a different host OS (FreeBSD can do this) that will allow you to manually load/unload support dor different divices.


macOS, especially with all of the new protections implemented in Catalina won’t allow you to do this.