So that leads me directly to this old bug: 215167 – Bluetooth: hci0: command 0xfc05 tx timeout
$ errno 110
ETIMEDOUT 110 Connection timed out
Basically, it means that the device is not fully initialized when the driver connects to it and the driver doesn’t wait long enough.
Maybe reloading the driver:
sudo systemctl stop bluetooth.service
sudo modprobe -rv btusb && sleep 10 && sudo modprobe -v btusb
sudo systemctl start bluetooth.service
Let a second terminal open and monitor dmesg:
sudo dmesg --follow-new