I have asus Bluetooth working OK with a Bluetooth mouse.
I have tried to use the GUI Bluetooth to add the keyboard.
the search finds the device…
the pairing/setup option lets me enter passkey or use random passkey.
when I enter the key on the device I get pairing in progress then after about 10-20 secs failed message.
I tried using Pi terminal window.
Device is listed OK
the bluez simple-agent not found
I tried installing on widow 10 laptop and had similar problems.
I am a beginner to Pi, but when I go from the main menu to preferences then to Rasp pi configuration I cannot find anything that looks related to device-tree.