Samsung Galaxy Note 8 Battery Draining Too Fast Issue (Resolved!)

To resolve this issue:

1. Use only 3G (Settings > Connections > Mobile networks > Network mode -> 3G only)
2. Use Medium Power Saving mode, no need to Restrict Background Data, only need to Limit the CPU's speed (Settings > Device care > Battery > Power mode)
3. Turn Data Saver on and allow only the following apps to use data in background:
1. Google Play services (might have two duplicate names)
2. Google Play Store (unless you can leave the screen open and active all the time every time there is a software update which I find it's quite annoying)
3.  All the instant messaging apps
(Settings -> Connections > Data usage > Data saver)

With these settings, when you don't use your phone, the battery level will go down very slowly.  The battery level will go down only when you use your phone.  Full 24 hours is now possible.