A look in battery and device care section, go into the battery and see what is using the battery most. Gives an indication Also make sure all apps are upto date. Not just on the Playstore, but the Galaxy Apps as well Could be and app or theme that's not playing well with the updated software
Power off your device, and plug into a pc. Or use a set of USB-C headphones. Simultaneously press and hold the Volume Down + Power buttons, when you see the Samsung logo release buttons. Use the volume buttons to navigate the Recovery Mode menu. Use the power button to select Wipe Cache Partition. Wait for the system cache partition to clear. You can also repair apps while in recovery mode. Good guardians is also good to download from the galaxy store. Run app booster.
Oh no definitely not right. Erm have u tried power saving mode I know its not ideal I have it on but given I have a23 128gb. Test it out. Also make sure location off .