Norton 360 on my iPhone 11 with all the latest updates-Battery drain excessive-over 90%. I cannot find any options for power usage.
[Edit: Clarified title]
Have you had Norton installed on your device for some time, and it just now started using a lot of battery?
It is normal for Norton to show a high % of your battery use as it is checking every file and process running on your device, and every web site you visit. See this Norton Support article. https://support.norton.com/sp/en/ca/home/current/solutions/v129651410