I understand people are suggesting to turn off screen time, don’t use fb and WhatsApp etc but that won’t fix anything.
This is my usage after taking off charge 11 hours and still on 50%. I Always use backup to restore since original iPhone , using iPhone X with battery health 98%.
I know battery took dive after iOS 12 release but Turning off features won’t help in my opinion, this need to Fix from apple side, I don’t kill apps in background except fb and gps apps.
Your picture showed some hours with a lot more usage than other times - do you know what you were doing during those times? Maybe some apps don't run well under IOS 12. Did you do anything different during those times or were you on cellular vs. WIFI?