I am having a similar problem. On my Windows 10 (1903 build) I can see the device in the Bluetooth search window, but then pairing doesn't work and it asks me to try again. I managed to connect it to my work Macbook Pro but then it has terrible lag, causing missed letters and repeated letters. Only works in wired mode which is not what I bought a wireless keyboard for. Pretty disappointed with a keyboard that costs over €100 yet fails with something as common as Bluetooth.