Now you can see from yesterday 9PM till morning 9AM the battery drain was minimum. while the phone is in use with apps like instagram, it normally consumes more power and the drain started to happen. you have charged again around 10% and now started using it.
If we start the day with 80 or 100% battery power and by the end of the day it comes around 20% nearer, then thats a good backup. with varying mobile network conditions, apps usage and display brightness level.
Do check this episode once and you can measure battery graph yourself tomorrow and day after if you want to perform the same check.
iOS 18.2 update coming up next week also fixes more bugs and you will see improvement bro.