having had the old 2016 SE, i can say the battery life is a dissapointment. sure the battery does not drain fast while in use but the idle standby time has worsened alot. The old 2016 SE would quite consistenly drain about 3-5% of battery through a 7 hour night and with very light usage (which is my case) i would get even more than 5 days. I had 2x SE 2016 (64 gb and 128gb) and it was about the same. now this is 4 years and 4 generations newer, also has a slightly larger battery, and it consistently drains about 7% per night.
quick maths conclude its about twice less efficient in standby time. the findings at gsmarena battery life tool indicate this as well...

overall with alittle less light usage the battery in the end turns out same or worse as the smaller SE for me, which is dissapointing considering all the talk about super efficient A13... maybe its not the A13 fault but the standby time is s*** regardless.
i wish more effort would be put into idle efficiency, the reviewers also seem to not care much about it

The low power consumption is insane and really goes to show how well optimized apple hardware and software is.

Is that an identical screen to my 2015 Apple iPhone 6s?   This thing even weighs more.   Pfft.