that is normal bro. around 10 to 12% is normal for apple watch. sleep tracking feature use pannumbothu latest watchos la upto 20% varaikum reduce aagumnga. I have tested it in the past one week.
Fast charging support irukarathaala. just 20 to 30 minutes watch a charging la place pannunga. that will be good practice to continue. morning namma ready agura time la charge pannitu continue pannalaamnga.