Bluetooth connectivity

I've got a new phone (Redmi Note 13 Pro) & new watch (Garmin Vivoactive 5) & I can't seem to keep the Bluetooth connected. The watch is connected via the Garmin App but that's it I can't get any notifications whatsoever to my watch ..... Never had a problem with my old phone (Huawei) or Garmin Vivoactive 4s ..... Tried everything, read everything ...... Can anyone help before I throw both watch & phone TIA