Go into your wear app, open watch settings. Then go to accounts and backup. Make sure you have save backup to Samsung cloud toggled on. Also make sure you have smart switch installed. It's smart switch that backups your watches data when connected to your phone.
Did you manage to solve this. I'm just curious as I looked in settings and came across the times of back up. Was just wondering if you turn off your devices at night?
Thank you. It does seem to be working now. I do keep the phone on charge and wear my watch at night. For the sleep app. Since I started this, things seem to be have improved.