The simple fact with MIDI is that every device needs a driver. This should work via BLE as Windows can see and attempt to pair with xkey but fails with yellow refusal/retry message.
By the way class compliant means BARE MINIMUM. So that not only do Xkey air NOT connect via Windows BLE, (and I’m not going to buy a Widibud when my Yamaha’s BT01 transmits fine, and windows can see Xkey but not connect just as Xkey attempts fail over android where I recieve the message “bad private key”) but also now barely hold a basic Class Compliant MIDI channel. Todays livestream I demonstrate that using my current cocktail of DAWs the xkey disconnects recurringly from 52:30 thru the end, at least 10 times: I have shown time and time again (in my livestreams) that MIDI devices do not work right without a driver.