Hi
I am currently on ios 18.5 and I could experience a battery drain up to 6 percentage when left unused at overnight even my background app refresh and location services setting is also toggled off.
I am quiet answer less for this issue
hi bro, overnight upto 10% is normal. depending on system services running, network service and any apps notifications does consume some power. so within 10% is normal dont worry.
continue with the charging practice as suggested in our channel and long run it will help to maintain bro.