We always want your device to work properly. Sorry to hear that this is not happening with your battery. Let's get this fixed. Have you powered the device off/on since performing the software update? What Samsung model device do you have?
I too am having serious battery draining issues on my Galaxy S10 after being forced to download the latest Android 11 update. Samsung pulled this update due to bugs, yet Verizon continued to push the update to devices with known issues and bugs. How is this acceptable? And I want to roll back to the old version so please advise.
As a consumer, I know important it is to have a battery that works as intended, Audi_time. While it is impossible to roll back to the old version, you can run the Samsung software repair tool as per this link (https://www.verizon.com/support/knowledge-base-80201/) to resolve any post software update issues. Keep us posted.