It doesn't help that Apple is making bad 'design' choices such as the one that control center doesn't really turn off bluetooth (https://www.cnet.com/uk/how-to/how-to-really-turn-off-blueto...). People can't understand every little thing draining the battery when this sort of thing is put in by design.
My personal experience: I never turned off Bluetooth or WiFi or 4G. With iOS 10, before going to sleep I'd put my iPhone 7 in Energy Saving mode and it's battery would go from 100% to 99-98%, now with iOS 11 it's going from 100% to ~90%. So I'm guessing the battery draining is coming from other places.
