Having issues with connecting to Bluetooth devices. Couldn't connect at all with Yunmai scale. Bought new Wyze scale because of that and had issues connecting with that. Solution was to go into and out of airplane mode to reset radio hardware/ software.
Not unique to scale, having same issue with fitbit which uses Bluetooth LE. Wouldn't sync today until I took my fictional plane trip.
Suspect hardware / drivers on GS21 because this was rock solid on my GS10.