As of now, the following models that support Bluetooth connectivity are Inspiroy Dial 2(Q630M), Inspiroy Giano(G930L), Inspiroy Keydial(KD200), Keydial mini(K20) and Huion Note(X10).
How to disconnect Bluetooth manually on those above models.
Inspiroy Dial 2(Q630M): Press the button on side and hold it for three seconds
Inspiroy Giano(G930L): Press the button on side and hold it for three seconds
Keydial mini(K20): Press the first row of four buttons simultaneously and hold them for three seconds
Huion Note(X10): Press the function button in the upper right corner and hold it for three seconds
Inspiroy Keydial(KD200):
It doesn't support Bluetooth disconnection manually. What you can do is turning off Bluetooth of the device connected to Inspiroy Keydial(KD200).