That's pretty common after a major software update.
I suggest you do the following:
- Find out what apps are using the most amount of battery/resources. If it's a 3rd party app, update it or downgrade it by downloading an old APK.
- If it's a system app, then let the update optimize everything for at least 3-4 days. The software will analyze your usage patterns and use resources accordingly.
If this did not help you, you may refer to this guide to fixing the battery drain on most Galaxy smartphones.
if the optimization doesn't help and this drain issue persists after a week then when you see a large drain that seems like it's not normal... submit an error report to Samsung Members app.