As convenient as backups might be, I totally started this phone from scratch. So far so good, battery, performance has been great.
I also check if ANY rouge apps are running constantly in the background that may cause battery drain. (I swear, the past 4, 5 iOS updates in the last phone this problem arises)
Go to Settings >Battery > Look at the chart, especially hours when you're not using your phone..see if anything is running. Could be Mail.app, (iTunes, Dropbox..)
Now right now, I have "Find My..." app running all the time. (This connection to Air Tags I suppose) But for some reason Siri was running a few times overnight. Woke up with 3% battery drain...past few days I would wake up with 0-1%. Just have to tweak some settings with Siri.
ALSO...I always go through these videos on YouTube, nonsense you can turn off to save some battery life, improve privacy as well. Helps with all these massive major updates each Fall.
Older video, but still helpful