The battery of my note 10 plus 5G was incredible! Now after UI 2.5 update, the battery dies very quik! Before update i was using my phone 2 days with one charge. Now i have to charge it twice to use the phone in one day! The ui 2.5 has a realy bad problem!
Can you try a few things please.
1. Turn the phone Off and then from a set series of button presses go into the phone's system files and clear the cache files. No info is lost this way.
2. If no help put the phone into Safe Mode which disables downloaded apps but leaves the stock one's working and then see what happens. Also check all apps have no updates pending. If the issue stops in Safe Mode then one or more of your apps are not optimised for the new update. It'll be a matter of un installing one at a time until it improves to find the rogue app(s)
3. If that does not work then as a very last resort back up and remove any relevant Sd card and factory reset.
4. A Samsung Experience Store or Samsung Service Centre can run a diagnostic test.
I wish you all the best with this situation.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.