My previous Keychron would lose the wireless connection if I ever used the mousing-keys (may have been missing udev rules) , so I had to keep it plugged in. I have the keyboard in my lap, and the usb-connector obviously broke after a couple of years. Managed to order a new daughter-board, but it seems to have disappeared in transit. Got a magnetic connector between the keyboard and cable for the new one. On the bright side, wireless works perfectly on the new keyboard. @keychron