It depends on so many factors, such as the number of applications you regularly use, the network strength in your area, your personal usage pattern. Most probably you need to turn on Adaptive Battery setting. By default it stays off. Try it out and see if there's a difference.
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question) along with screenshots, short videos and error log file, so that we can assist you accordingly.
Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
Thanks for the update,are you able to go through the day,with a single charge? How much SOT are you getting,is there any improvement post UI 3.0 upgrade. Some people suggesting to limit the functions to save power such as dark theme/Sync off etc. which appear like an adjustment and helpless condition due to poor battery design.
