I'm a Samsung user from 10 years and this is the worst mobile made by Samsung.
well..... 25 % drop in battery = 2 hrs.
100% drop in battery = 8 hours (assuming)
it is not bad but average and you can improve it .
At first place, factory rest your phone after backing up data. resetting phone is the solution of many problems particularly after updating.
Secondly, turn off unnecessary features which use phone sensors. ( there may be 42 sensor related features in ur phone) Advance features > motions and gestures
turn off wifi and Bluetooth scanning along location if it is not in use.