Even a good battery isn’t that good. That seems to be a software problem.
My only theory is it’s turning on the screen every time it gets a notification. However, I have a case that covers the screen, which should keep the screen off in my opinion. I have thought about disabling 100% of the notification, but without a global toggle that seems pretty annoying to do.
That's abnormal.
If it's malware, do a clean reinstall from DFU mode using Apple Configurator on a Mac.
What does Settings > Battery > "Battery Usage by App" show as the top consumers of power?
Does "Low Power Mode" make any difference?
When I looked at the top battery consumers in the past there wasn’t anything that stood out. I think home screen was at the top. It wasn’t one or two apps killing it with background activity.
Since the biggest battery consumption associated with home screen is the display, and users are only briefly on the home screen, before using it to navigate elsewhere, home screen should be near the bottom (1%) of power consumption.